Refactoring with fixing potential bugs
A bit refactoring
Tiny fixes to prevent possible bugs
Added support of parsing new layers organization (need test deeply)
Optimization - if movieclip has totalFrames == 1 creates sprite instead movieclip
Refactoring and comments
Cleanup code
Added new parsing of layers. Refactoring
Added parsing external graphics and add new layer params (camera position and camera mouse enable)
Added assembling external graphics, refactoring. (Still need rework adding camera, but first need to do appropriate changes in engine)
Fixed comment
Implemented new layers and cameras organization
Reworked related to new layers and cameras organization
removed 'keepGroup' from layer
Now layers and cameras creates correctly
Support parsing and assembling  new properties 'repeatable' & 'keepSequence' of  graphics scheme
Clean code
Added addition layer's names constants
Property 'isCulling' moved to BBRenderable. Now for each renderable component it is possible to set own value. For BBRenderable fixed setting of 'blendMode' param
Fixed architecture problem of dispose method of BBComponent class.