[tutorials]more work on describtions (issue #91)
Includes cleanup
[ios]Define _DEBUG for iOS debug configuration
[dependencies] Delete old useless GLES directory.
[engine]Removed lookAt API on renderer, as it seems to be legacy 3d methods. Not used now, and it brings less architectural decisions with GLES. Will reintroduce it later on if needed anyway
[engine]Adds matrix multiplication in place, identity matrix initialisation.
Merge branch 'master' of github.com:DarthMike/indielib-crossplatform
[engine][gles]#100 #58 Sets up basic environment for GLES to render. All rendering methods disabled, will reintroduce them one by one, as API change is needed.

Side change promotes IND_Matrix to a class. Will go in a different header file in next changes, as it is to sit next to IND_Vector2 in our library types.
[engine]Fixed TODOs.
Bump version to 0.6
[engine][gles]#58 missed glsl shading language version. Minor log formatting.
Merge remote-tracking branch 'origin/master' into truetype