Refactoring of H3M loader to make HotA format support easier

- extracted low-level reader from MapFormatH3M class
- added separate structure to define version-specific values
- cleared up some H3M format edge cases
- replaced witch hut skill vector with set
- converted several fields to enum type

lib/mapping/CMap.h

@@ -86,17 +86,9 @@ struct DLL_LINKAGE PlayerInfo
 	int3 posOfMainTown;
 	TeamID team; /// The default value NO_TEAM
 
-
-	bool generateHero; /// Unused.
-	si32 p7; /// Unknown and unused.
-	/// Unused. Count of hero placeholders containing hero type.
-	/// WARNING: powerPlaceholders sometimes gives false 0 (eg. even if there is one placeholder), maybe different meaning ???
-	ui8 powerPlaceholders;
-
 	template <typename Handler>
 	void serialize(Handler & h, const int version)
 	{
-		h & p7;
 		h & hasRandomHero;
 		h & mainCustomHeroId;
 		h & canHumanPlay;
@@ -111,7 +103,6 @@ struct DLL_LINKAGE PlayerInfo
 		h & generateHeroAtMainTown;
 		h & posOfMainTown;
 		h & team;
-		h & generateHero;
 		h & mainHeroInstance;
 	}
 };
@@ -259,20 +250,17 @@ struct DLL_LINKAGE DisposedHero
 	}
 };
 
-namespace EMapFormat
-{
-enum EMapFormat: ui8
+enum class EMapFormat: uint8_t
 {
 	INVALID = 0,
 	//    HEX     DEC
-	ROE = 0x0e, // 14
-	AB  = 0x15, // 21
-	SOD = 0x1c, // 28
-// HOTA = 0x1e ... 0x20 // 28 ... 30
-	WOG = 0x33,  // 51
+	ROE  = 0x0e, // 14
+	AB   = 0x15, // 21
+	SOD  = 0x1c, // 28
+	HOTA = 0x1e, // 30
+	WOG  = 0x33, // 51
 	VCMI = 0xF0
 };
-}
 
 /// The map header holds information about loss/victory condition,map format, version, players, height, width,...
 class DLL_LINKAGE CMapHeader
@@ -293,7 +281,7 @@ public:
 
 	ui8 levels() const;
 
-	EMapFormat::EMapFormat version; /// The default value is EMapFormat::SOD.
+	EMapFormat version; /// The default value is EMapFormat::SOD.
 	si32 height; /// The default value is 72.
 	si32 width; /// The default value is 72.
 	bool twoLevel; /// The default value is true.