- Fixed mismatched alloc/dealloc in FTextureManager.

The 'TextureFrames', which is attached to all the 'mAnimatedDoors', were deleted with one-pointer 'delete' and they were allocated with 'new[]'.
Merge branch 'maint' of https://github.com/edward-san/zdoom into maint
Merge branch 'maint'
Merge branch 'master' of https://github.com/rheit/zdoom