physac modules is being redesigned. Physics base behaviour is done and
it is composed by three steps: apply physics, resolve collisions and fix
overlapping.

A basic example is currently in progress. The next steps are try to add
torque and unoriented physic collisions and implement physics basic
functions to add forces. Rigidbody grounding state is automatically
calculated and has a perfect result. Rigidbodies interacts well with
each others.

To achieve physics accuracy, UpdatePhysics() is called a number of times
per frame. In a future, it should be changed to another thread and call
it without any target frame restriction.

Basic physics example has been redone (not finished) using the new
module functions. Forces examples will be redone so I removed it from
branch.

A deeper revision required, not clear enough for the user
Key: Create a PhysicObjects pool

- Added function WorldToScreen(...).
- Added world to screen example.
- Review GetMouseRay() comment.
- Removed deprecated lighting functions from raylib header.

Simplified for the user (more intuitive and clear)
Removed lighting module dependency

- Added CheckCollisionRayBox() function.
- Updated and improved core 3d picking example (currently working as
expected).

Two new functions added to save/load values as binary data:
- StorageSaveValue()
- StorageLoadValue()

New physics example to see AddForceAtPosition() behaviour applied to 5
rigidbodies.

- Added new physics engine-module with four new data types: Physics,
Transform, Rigidbody and Collider. This library contains functions to
apply physics calculations to a position vector calculating collisions
automatically.

- Fixed some writing mistakes of lighting module.

- New lighting engine module which contains new data types Light and
Material. These data types and functions facilitates making a basic 3D
iluminated program with a light and a model.

- Added lighting engine module example (currently included in raylib.h;
it might be compiled by separate and include lighting.h in game source C
file).

- Corrected some opengl defines control structures and added some TODO
to fix raylib-opengl 1.1 source build (note: now source can be compiled
without errors, but rlglReadPixels() won't work properly).

Note: most of functions of phong version 330 shader are not in v100
shaders, so I couldn't write a version 100 phong shader. These functions
are included from version 150.

Probably more useful...