added new 'execute' utility function and using it in RenderTexture
simplified and optimized 'execute' function
... and a little more
added protected property allowing access to objects vector (closes #515)
Removing dead code

Small change to remove dead code that triggers warnings in some editors/code analyzers. No change of functionality.
Merge pull request #521 from zeh/patch-1

Removing dead code
disabled strict mode for asdoc compilation (closes #518)
added 'muted' property to movie clip (closes #519)
now optionally keeping atlas and font XMLs in AssetManager so that they can be accessed later (refs #445)
Added static all property to get all Starling instances (an instance is added in constructor and removed on dispose).
asset manager now checks http content-type if no file extension is available (refs #526)
Merge pull request #527 from joshtynjala/all

Added static Starling.all property to get all Starling instances
corrected indentation
added property 'numCurrentTouches' to touch processor
now checking if context is valid when dispatching RESIZE event (closes #528)
now cloning texture options to allow usage of the same instance multiple times in one queue
added 'repeat' property to TextureOptions constructor
to avoid overloading time-based animations, the maximum delta is now truncated (closes #500)
added 'touchGroup' property to containers, similar to 'mouseChildren' (closes #348, refs #83)

better late than never, right? ;-)
updated asdoc description (refs #348)