sound system
missed on first commit
fixed brackets style
fixed some code style and error
added some comments
added support for basic 3D sound
fixed the singleton to threadsafe pattern
json file for audio settings
added sounds to sample.json instead
Sanity check to make sure the sound file is good before playing
Merge branch 'develop' into feature-sound-system

Conflicts:
	src/main.cpp
	src/systems/json-parser-registration.cpp
	src/util/json-parser.cpp
Fixing assets
Merge pull request #1 from adam4813/feature-sound-system

Feature sound system
Added bullet physics to CMakeLists and FindBullet.cmake
Add physics system and registered it with TrillekGame

There is a crash on exit that I can't determine the root cause
it might be linked to my runtime choice however.
Rough capsule shape used as a rigidbody

There is a default "ground" plane placed 10 units
down to provide a test bed of sorts.
UpdateTransform now uses quaternions

UpdateTransform in capsule shape was using rotation angles,
instead of quaternion orientation. Now it is updated with a
quaternion. To accomplish this Transform now has
SetOrientation which takes a quaternion.
Updated travis-ci to install bullet
Typo
One more attempt at bullet with travis-ci