DebugTools: this shouldn't be inline.
DebugTools: test orthogonality the easy way.

Brainfart.
DebugTools: orthogonal, not parallel.

Another brainfart.
Reword features in building documentation a bit.
Properly document building on Windows.
Minor Markdown reformatting.
TextureTools: fixed typo.
Updated .gitignore.

It would accidentaly ignore also doc/building.dox (which is wrong).
However it doesn't seem to do that.
Link with other projects' building and usage documentation.
Finally proper Getting Started Guide in documentation.