reopening c-initializer window caused segfault. no longer
now attribute with get/set operations can be freely moved and copied between classes
they take their respective getters/setters with them
relations can be duplicated as well
previous commti contained a problem that caused segfaults. It is fixed now
fixed segfault that was happening on repeated artifact dialog opening
 browser object diagra and object diagram window's relationship allowed
 already deleted pointer to be used for ->on_close
 I am not sure that what I did to fix this is corret. will need to review
 this commit when I am not as sleepy
Added a compatibility save mode for people who don't want to lsoe
compatibility with 4.23 yet
Merge remote-tracking branch 'upstream/master'

Conflicts:
	src/browser/BrowserDiagram.h
	src/browser/BrowserObjectDiagram.cpp
	src/browser/BrowserObjectDiagram.h
	src/data/OperationData.h