Fixed calculation of camera matrix.
Began refactoring Audio module.
Completed refactoring of audio module in engine.
Finished refactoring audio module.

Closes #25
Written note about equipment.
Removed audio source stop callbacks.

Though the audio module holds a reference to all active sources.

Closes #29
Documented audio module.
Implemented effects in Lua.
Refactored Lua code again.
Add more properties to solids.

Getters for linear and angular velocity, as well as getter and setter
for a solids restitution.

Closes #26
Added some notes on effects.
Built basic test system using TAP.
Wrote Vector test.
Updated lua-mock.
Fixed bug in EffectTarget.
Fixed bug in EffectTarget.

Closes #31
Merge branch 'feature/lua-tests'
Removed unused math functions.
Merge branch 'master' into feature/module-stubs
Updated gen_stubs script.