*. Line breaks for text. Need to alter estimateTextWidth and 
   getTextHeight, as well as drawtext to cope with them.
   getTextHeight will need to take the text as a parameter. All estimating
   functions will need to respond to \n in the text as a line break (the
   actual text, not charcode) and drawText will need to make multiple
   SVG text outputs according to the number of lines (adjusting y pos
   accordingly)

*. Support for notes. Notes should be another entity like classes etc.
   They can be placed as with other components and you can attach them
   to other entities as a relationship.
   entity note noteentity.

*. Investigate creating graphviz output

*. Colour and margin override for SVG output. Should be specified as
   part of the diagram. Perhaps have an enclosure:

   diagram mydiagram {
       visuals {
           entity_margin = 20;
           class_colour = #ff00ee;
	   usecase_colour = yellow;
	   package_colour = rgb(197,197,197);
       }
   }

   [ visuals enclosure is in as part of DiagramParser, but only supports
     entity_margin at present ]

*. Syntax highlighting for Eclipse plugin
