add jqs widget
spreadsheet for wip
make loadData() function.
add Load JSON button.
use val() instead of text() to replace data in textarea.
add a missing image.
add MachineJobShop, QueueJobShop and ExitJobShop.
height of the property dialog should be automatic.
make ID modifiable.
check existing ID before changing ID.
rename wip to spreadsheet because this spreadsheet will likely be used for other things as well

Also pass the the spreadsheet along the graph to the backend
Merge branch 'master' into jerome_jqs_for_wip

Conflicts:
	dream/platform/static/index.html
	dream/platform/static/src/dream_launcher.js
cleanup HTML and javascript.
extend skeleton css for wider screens.
add 'Import' functionality.
add 'Export' functionality.
no longer use id_container to generate a unique ID.
fix a bug in positionGraph() for node ids where we have no '-' sign.
support input data that has no coordinates information.
call jsPlumb.repaint(element) instead of jsPlumb.repaintEverything() in redraw()

otherwise connections will be rendered in wrong positions in case of calling /positionGraph.