Inability to draw feedback interactions

[conradderbyshire]

Feedback interactions (e.g. a repressor glyph inhibiting an upstream promoter glyph) are incorrectly rendered (see below). It does correctly start the interaction at the 'starting glyph' (SrpR in this case) but then goes left-to-right rather than back on itself to its 'ending glyph' (pSrpR).