Added touch joystick example

Using Clay.io's HTML5 Virtual Game Controller
add gamecontroller.js to view_lite.html for the side_view layout
update the collision hulls in sprite->sprite separations (in addition to sprite->tile separations)
Heavily optimised PixiShader.
Merge pull request #231 from jcd-as/dev

update the collision hulls in sprite->sprite separations (in addition to...
Preparing to extend the Loader to handle script loading.
New non-conflicting Loading system in place. Creating tests.
Lots of documentation updates and new Loader examples.
fix for ’jitter’ in scrolling where tilemaps & sprites are one frame off from each other
Fixes #214
Merge pull request #233 from jcd-as/dev

fix for ’jitter’ in scrolling where tilemaps & sprites are one frame off...
New filters and demos: LightBeams, Fire and Tunnel. Also Loader can now load script files.
Loader fixed for tilemap data.
Updated documentation.
Fixed filters for new shader code.
Caustics filter
Updated Filter resolution to a 2f and added Blur and Marble filters.
New Getting Started Tutorial.
Tutorial update.
Final version of the Getting Started guide.
Small link updates.