Making stuff
1. Changed main model to QFileSystemModel
2. Made different colors to dirs/files (again?)
3. Changed edge class so that it handles GraphItem-pointer
Stuff to make:
1. Fix edge drawing (draws only at a point, probably misses boundingRect
Fixed bug
Fixed wrong edges drawing with new edge class (with GraphItem *src,
*dest).
Merge branch 'master' of https://github.com/Zo0MER/graph_editor

Conflicts:
	graph_editor.pro.user
	graphedge.cpp
	graphedge.h