* disabled features unsupported by MinGW
* fixed issues with DLL_LINKAGE
! BOOST_THREAD_VERSION in now 3 workaround for existing code added, consider refactoring.
* some small tweaks ("-fpedantic" warnings)
* all lock/unlock and unlock/lock pairs are done by RAII guards now
* fixed two possible crashes at the end of battle when last stack was killed by spell. That should fix#749 and #752.
* fixed a very nasty race condition, eliminating possible deadlock at the start of battle when human hero has tactics
* fixed#422