Fix otherwise unset fragment alpha with VERTEX_COLOR defined.
Check built-in preprocessor macros to see if highp is available
Nullify second object in CollisionPair before notifying listeners after removal

By the time CollisionListener::collisionEvent is called, second object
in the CollisionPair is already deleted and points to an invalid memory
location.
Merge pull request #1373 from rgngl/alphaFix

Fix otherwise unset fragment alpha with VERTEX_COLOR defined.
Added basic support for setting and referencing variables in properties files via the syntax ${variable}.
Added two new methods on the Properties class, getVariable and setVariable.
Merge pull request #1376 from rgngl/shaderPrecisionFix

Check built-in preprocessor macros to see if highp is available
Merge pull request #1377 from rgngl/physicsRemoveFix

Nullify second object in CollisionPair before notifying listeners after removal
Updated lua bindings to support new methods on Properties class.
Merge branch 'next' of https://github.com/blackberry/GamePlay into next
Merge pull request #1378 from sgrenier/next

Variables support for Properties files
Merge remote-tracking branch 'blackberry/next' into dev

* blackberry/next:
  Updated lua bindings to support new methods on Properties class.
  Added basic support for setting and referencing variables in properties files via the syntax ${variable}. Added two new methods on the Properties class, getVariable and setVariable.
  Nullify second object in CollisionPair before notifying listeners after removal
  Check built-in preprocessor macros to see if highp is available
  Fix otherwise unset fragment alpha with VERTEX_COLOR defined.