added another item type 'attachment' into the graphics group
fixed the issues: cannot move all items in the group
can click attachment to open the file/URL
Limitation:all loaded attachments are overlaped
1. added QGraphicsProxyWidget test for QGraphicsItem class
2. support NodeBox can be adjusted by txt size and attachment numbers
1.fix some issues related to GraphicsItemgroup based NodeItem:
  move by mouse drag/release,resize when add link and attachment or
change text size using the unified redraw NodeItem
2. another method by using QgraphicsWidgetProxy to show a nodeitem with
UI (problem remained: proxy container's mouseReleaseEvent can block
nodewidget.cpp's same event,so current behavior is not moving as mouse's
point exactly)
Merge branch 'master' of https://github.com/xmd-project/prototype
Using sceneEvent() in QGraphicsWidgetProxy to fix the move/ mouse click
conflict issues
test git connection
The cleaned prototype of class node with data
Merge branch 'master' of https://github.com/xmd-project/prototype
Merge branch 'master' of https://github.com/xmd-project/prototype