Added Line Properties (LineJoin and LineCap) to Draw

Hi.
I've added two properties to the draw object that are available in agg: line-join and line-cap.

Simon


PS
The agg version used at the current aggdraw is 2.2, which is not the latest (2.4), which - among other things - introduced some changes in the API.
Do you plan to update the AggDraw anytime soon, to include agg 2.4?

PPS
I found some additional bugs in aggdraw - which in part led me to write the change I'm offering here - namely, when widening the stroke (pen) width in a polygon, so that it intersects itself, the creates weird effects.
Would you be interested in an example that would allow you to fix that at some point?

Regards,
Simon