Warnings fixes
* Suppress `missing-braces` for Clang
* Fixed many C4275 warnings
* Fixed almost all Clang/GCC warnings
* Silence most frequent MSVC warning.
* Fixed some pessimizing-move warnings
* Fixed some unused capture warnings
* attribute for battle image added on hero class, allowing on hero schemes each hero have a unique battle .def in 'images' structures sided with portraits and specialties images
New features for players:
* Loading for multiplayer. Any save could be used for multiplayer.
* Restart for multiplayer. All clients will restart together.
* Loading from single save.
* Hotseat mixed with network game. Multiple players per client.
* Now connection to server could be cancelled.
* Return to menu on disconnections instead of crashes.
* Restoring of last selected map, save or campaign on next run.
TLDR on important changes in engine code:
* UI: work with server separated from UI
* UI: all explitic blitting replaced with IntObject's
* UI: all new code use smart pointers instead of DISPOSE
* Gameplay always start through lobby controlled by server.
* Threads receiving netpacks now shared for lobby and gameplay.
* Campaigns: heroes for crossover now serialized as JsonNode.
* Universities, Scholars and Witch Huts may offer new skills
* Moved encode/decodeSkill to CSkillHandler
* Refactored CSkill interface and CSkill::LevelInfo image storage
* Legacy game constants renamed to ORIGINAL_XXX_QUANTITY
Addresses several related problems:
* Propagation / unpropagation of duplicate bonuses is inconsistent, causing bugs
* Duplicate bonuses never stack, which is not always intended behaviour (e.g. multiple copies of resource generating artifacts)
* Different bonuses always stack, which is not always intended behaviour (e.g. Angel + Archangel morale bonuses)
This is addressed as follows:
* Duplicate bonuses are never eliminated during propagation/inheritance.
* Unpropagation eliminates only a single copy of duplicated bonus
* Bonus receives a new field stacking that determines stacking behaviour:
* * empty string = no stacking with duplicates (default)
* * "ALWAYS" = stacks with duplicates & everything else
* * some other value = no stacking with bonuses with same stacking value
Also Morale/Luck window now hides non-stacking bonuses.
* changed Bonus::additionalInfo to integer vector
* fixed deserialization for old savegames
* removed newline from JsonNode::toJson()
* updated bonus schema; SPELL_AFTER_ATTACK and SPELL_BEFORE_ATTACK use new addInfo format
* removed unnecessary init in Bonus constructor
* Indirect spell effects loading
* Json serializer improvements
* spell->canBeCastAt do not allow useless cast for any spell
* Added proxy caster class for spell-created obstacles
* Handle damage from spell-created obstacles inside mechanics
* Experimental GameState integration/regression tests
* Ignore mod settings and load only "vcmi" mod when running tests
* fixed https://bugs.vcmi.eu/view.php?id=2765 (with tests)
* Huge improvements of BattleAI regarding spell casts
* AI can cast almost any combat spell except TELEPORT, SACRIFICE and obstacle placement spells.
* Possible fix for https://bugs.vcmi.eu/view.php?id=1811
* CStack factored out to several classes
* [Battle] Allowed RETURN_AFTER_STRIKE effect on server side to be optional
* [Battle] Allowed BattleAction have multiple destinations
* [Spells] Converted limit|immunity to target condition
* [Spells] Use partial configuration reload for backward compatibility handling
* [Tests] Started tests for CUnitState
* Partial fixes of fire shield effect
* [Battle] Do HP calculations in 64 bits
* [BattleAI] Use threading for spell cast evaluation
* [BattleAI] Made AI be able to evaluate modified turn order (on hypothetical battle state)
* Implemented https://bugs.vcmi.eu/view.php?id=2811
* plug rare freeze when hypnotized unit shots vertically
* Correctly apply ONLY_MELEE_FIGHT / ONLY_DISTANCE_FIGHT for unit damage, attack & defense
* [BattleAI] Try to not waste a cast if battle is actually won already
* Extended JsonSerializeFormat API
* fixed https://bugs.vcmi.eu/view.php?id=2847
* Any unit effect can be now chained (not only damage like Chain Lightning)
** only damage effect for now actually uses "chainFactor"
* Possible quick fix for https://bugs.vcmi.eu/view.php?id=2860
* it is possible now to add casts and shoots OTF (f.e. with spell bonus)
Centralized stack 'ammo' loading from bonus system.
* introduced small proxy class for local bonus cache
(no need to use global cache if particular selector used on node only in one place)
* handle killing resurrected creatures
* use IBonusBearer::MaxHealth() where possible
* Fixed https://bugs.vcmi.eu/view.php?id=2486
* Possible fix for 0 HP after resurrection.
* Hack-fixed https://bugs.vcmi.eu/view.php?id=2584
* Unified CStack health API
* Use CHealth for CStack count and health points
* increased SERIALIZATION_VERSION
* Added experimental support for cumulative effects for ENCHANTED bonus
* Updated and fixed SPECIAL_PECULIAR_ENCHANT processing
* Initial implementation of cumulative spell effects.
* Scheme for new spell feature - cumulative bonus.
* Avoid server crash on dummy connect / disconnect.
* Avoid server crash when host left from PreGame.
* Server print it's state with name when it's waiting for connection or in pregame.
* Server will use random port if specified port is busy.
* Hero portrait serialization
* Fix town spells serialization
* Added support for float exponential part in Json
* Added support for int64 in Json
* Added basic Hero definitions serialization
* Added rumors serialization
* Advanced player info serialization.
* Added Disposed heroes serialization, (!) not covered with tests yet
* Added Local event serialization
* Added Pandoras box serialization
* Added Seer hut reward serialization
* Added CQuest serialization
* Added API for map object instance names serialization.
* Added random dwelling options serialization
* Advanced town options serialization
* Advanced hero options serialization
* More map format tests
* A lot of fixes, cleanup and refactoring
