fixes #63
fixes #63

Conflicts:
	d3/UpdateViews.js
fixes #49
Merge branch 'PDP' of https://github.com/renoust/TulipPosy into PDP

Conflicts:
	d3/Client.js
server: induced subgraph now replaces current graph should fix #55 (not tested yet)
client: now updating only given properties in graphs from layout and float algorithms should fix #68
Merge branch 'PDP' of https://github.com/renoust/TulipPosy into PDP
fixes #51 and #48
Merge branch 'engine' into PDP
Merge branch 'interface' into PDP

Conflicts:
	d3/TulipPosy.js
	d3/UpdateViews.js
Merge branch 'PDP' into interface
don't create buttons if they are already here
Fixes #74