New build script now cleanly splits Phaser, Pixi and p2 so they are each UMD wrapped and each available in the global scope (now more requireJS friendly!).
phaser-no-libs.js allows you to use your own version of p2.js or pixi.js with Phaser. Warning: This is totally unsupported. If you hit bugs, you fix them yourself.
Fixed silly instanceof bug in game objects (sorry guys).
You can now safely destroy a Group and the 'destroyChildren' boolean will propogate fully down the display list.
Calling destroy on an already destroyed object would throw a run-time error. Now checked for and aborted.
Calling destroy while in an Input Event callback now works for either the parent Group or the calling object itself.
In Group.destroy the default for 'destroyChildren' was false. It's now `true` as this is a far more likely requirement when destroying a Group.
All GameObjects now have a 'destroyChildren' boolean as a parameter to their destroy method. It's default is true and the value propogates down its children.
fixedToCamrea now works for Groups as well :) You can fix a Group to the camera and it will influence its children.
Also fixed the issue with World.preUpdate/postUpdate not being called and various small documentation issues.
