World.camera should be favored over HXP.camera.

HXP.camera is used mainly as a fallback camera for rendering an entity
that is not added to a world in FP.
Merge branch 'master' of https://github.com/MaskedPixel/HaxePunk into MaskedPixel-master
Merge branch 'MaskedPixel-master'
Fix debug renderEntities when entity's scroll is != 1

Without it, the debug rectangle has a wrong offset.
Added _world == null test for inline onCamera function
Added a cross method to Vector so you can get a cross product
Merge pull request #87 from julsam/debug-render

Fix debug renderEntities when entity's scroll is != 1
Merge pull request #88 from DjPale/upstream-master

Added _world == null test for inline onCamera function
Merge pull request #90 from thecodethinker/master

Simple Cross method in Vector class
Several fixes (Rotated AtlasRegions, Text, TextureAtlas)

Fixed: Rotated atlas regions were rotated the wrong way.
Fixed: Images reported the wrong width and height when it's source was a
rotated atlas region.
Fixed: When text removed itself from it's parent, _parent should be set
to null.
Clarified some documentation for TextureAtlas.loadTexturePacker.
Fixed:  Use of deprecated variable _world.

In Entity.get_onCamera, _world was used and should be _scene.
Fixed: Text width/height using hardware rendering.
Merge pull request #94 from MaskedPixel/dev

Several fixes (Rotated AtlasRegions, Text, TextureAtlas, Entity)