Make the entitiy spacing dependent on the number of entities.
  i.e. 2 entities are more spaced than an MSC with 8.

Add arrowsize option (global and with per-arc overrides).

Add option to change broadcast arc representation.

Add in the text background colour patch.
  (Also add white background to text in SVG and EPS output)
  
Fix cygport build (required gdlib.pc to be available somewhere)  