Fix some valgrind memcheck warnings. However there remains one...

... within the threaded texture cache. Once it is resized, some textures
in GetQuad(...) (WCachedResource.cpp:102/103) have uninitialized widths/heights.
Merge pull request #561 from ZobyTwo/valgrind

Fix some valgrind memcheck warnings. However there remains one...

... within the threaded texture cache. Once it is resized, some textures
in GetQuad(...) (WCachedResource.cpp:102/103) have uninitialized widths/heights.
Fixed wrong activation cost in dragon hatchling
Small fix in match_and ( [-color1; -color2] was handled incorrectly )
Merge pull request #560 from ZobyTwo/dead_code

Remove some dead code
Merge branch 'cmake' into SDL2

I cant get the pro file to work so I try my luck with cmake. I may cherry-
pick relevant patches afterwards.
Port to SDL2
Merge branch 'SDL2' into cmake

This allows to test build in sdl mode