Change diff form behaviour
Add a new class for storing parent information
Add new stuff
Make treeNodeSelected virtual method
Merge remote-tracking branch 'origin/change-diff-form-behaviour' into change-diff-form-behaviour

Conflicts:
	rbkit-lib/ui/diffviewform.cpp
Start splitting heapitem into different methods
Extract diffitem in its own class
fix compilation
Add a baseheapitem that implements basic
implementation
Start properly implementing subclass of baseheapitems
Refactor heapitem into different classes
remove some not needed methods
remove not needed methods
move heap items to its own folder
remove needless getIsSnapshot
remove unused reference item
remove unused diffitem file
Fix usage of heapitems
Fix compilation behaviour after refactor
Fix more compilation errors