Added classes to represent special actors in PiMM (broadcast, join, fork) and modified PiMMVisitor and its subclasses to take these new classes into account.
Added a type attribute in Fifo class, representing type of the data tokens in the fifo.
Modified PiMM2SDFVisitor wrt. attribute type of Fifo.
Added a feature Set Data Type on Fifos in the editor (right click on a Fifo to access it).
Added features to create Broadcast, Join and Fork actors in PiMM editor.
Merge branch 'PiMM-typed_fifos' into develop