A3DGE Code

* Fixed components: They didn't got the Owner pointer!!!
+ Started with backgrounds and models, and added functionality to Entities, and
cameras, so it is able to render things in a 3D space!

+ Added camera setup.

* A few changes in the "Entity" and "Object3D" design.
* Documentation updates for such changes.

[Emergency commit to avoid loss 'cause my computer is doing weird things]
+ Added function a3dIdentityMatrix.
+ Added units a3dge.Models, a3dge.Materials, a3dge.World3D and
a3dge.OctreeWorld3D with scafolding of the 3D space subsystem.
* Documentation completed and fixed.

+ Added a few more matrix operations.

+ Added Ta3dMatrix3D.
+ Added another way to build a gnomon.
* Documentation updates.

* Fixed makefile.
* Fixed ex_test_components.
+ Added vector functions and methods.
+ Added Gnommon build routines.

+ Added unit a3dge.Math3d with Vector3D definition an a few functions.

* Fixed a3dLoadBitmapFont: It raised an exception if it couldn't load bitmap
from disk.
+ Added Allegro's TTF add-on to application initialization.
* Fixed examples.

- Removed demonstration game: internal design is too different than the new
game engine. Will rewrite when engine is more complete.
* Ta3dKeyboard.Initialize doesn't check if there's a keyboard handler and
installs its own handler in any case.