relative path to pointed object method in serializer helper
wrong serialization order in PlaceAtBrick
fix wrong xml-tag-name for LoopEndBrick
fix pointToBrick pointedObject serialization
remove spriteobject list sorting stuff
reenable serialization in saveToDisk
Merge branch 'issue#395' of github.com:Catrobat/Catty into issue#84

* 'issue#395' of github.com:Catrobat/Catty:
  fix compile issue
stack to keep track of current position
replace old import statements
renamed GDataXMLNode+CustomExtensions to GDataXMLElement+CustomExtensions
using stack to keep track of current position during the serialization process
fix compile errors
fix all remaining compile errors
always pop xml elements from stack when addChild is called
refactor serializer so that xml-attributes are never added to the stack
debugged and fix formula stack issue
fix serializer stack issue in BroadcastScript
finish stack implementation
handle path storage of pointed and spriteObjects
shallow copy for VariablesContainer