rhizicore: fix popping node on top left when creating a new node
rhizicore: fix popping node on top left when creating a new node

The fix is ugly. Basically we are relying on the force layout [1] for
the locations of the nodes. I've hidden the node until the first tick.
Since we do a tick calculation (tick is a function in rhizicore) when
adding a node there is no associated delay.

[1] https://github.com/mbostock/d3/wiki/Force-Layout

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