Added direct node editing from within IPE (Reviving this module a bit)

Reviving this module a bit since it kinda suits my basic needs. I just added the possibility to directly edit a node when clicking on the configure button of a pane. It basically acts the same as the "New " functionality, instead it loads the node form in edit mode instead of 'add'.

The patch also contains the other modifications (see the info file for whats added).