Add call to code to calculate width for variable width features, e.g. homologies. Fix small bug in intron draw code which makes feature too wide.

get text drawn like any other column, and fix up the positioning of columns, still some work to do on this.

ITEM_FEATURE_BOUNDING_BOX.  These items are transparent and have their
fill_color_gdk set to null but the g_object_get gets the colour of the
item below. Not quite as expected.

unhighlight   is  now  just   a  reverse   video  operation   with  no
consideration  of   style.   That  would  have   involved  looking  at
background or foreground and ... this is just easier.

Uses the same code from foo-canvas-rect-ellipse.c.
Not sure why there was a difference, but was causing multiple glib errors

(zmap:20446): GLib-GObject-WARNING **: invalid cast from `FooCanvasPolygon' to `GtkWidget'

and seg faulting.

It uses James' PerlModules.  We could do with an AcePerl version.

think it's all fixed now

take notice of align_gaps in style

ZMAPFEATURE_ALIGNMENT lines are able to have gaps!