rz_core: cleanup node click handlers
rz_core: cleanup node click handlers

too much work to split right now. Following changes:

click handlers on circle and on text.
image is now under circle instead of side by side (otherwise it hides it
due to same z-index and later in children list)
some methods renamed to indicate first parameter (editNodeText,
showNodeInfo).
less calls to graph_update.

Still doesn't fix the selection (i.e. unselect for reclick).

shlomif/rhizi,yuvadm/rhizi,cben/rhizi,Rhizi/rhizi,ozFri/rhizi,Rhizi/rhizi,cben/rhizi,ozFri/rhizi,tlevine/rhizi,shlomif/rhizi,tlevine/rhizi,tlevine/rhizi,Rhizi/rhizi,Rhizi/rhizi,shlomif/rhizi,cben/rhizi,shlomif/rhizi,ozFri/rhizi,yuvadm/rhizi,tlevine/rhizi,yuvadm/rhizi,yuvadm/rhizi,cben/rhizi,ozFri/rhizi