Lanes are going to be modeled via the parents context-pad only.
This commit
* removes lanes from the palette
* adds lane actions to the context-pad
Related to #379
This adds space-tool and lasso-tool as required modules to the BPMN
palette. That in term ensures that users can simply reuse the palette
without further configuration.
This commit adds the ability to model participants from the palette.
* Empty diagrams can be used as a start for participant _AND_ process diagram
* Process diagrams can be converted to collaboration diagrams by dropping
a participant onto them
Closes#128