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.