SDWF 0.59 maintenance release

[Stewart Gordon]

A tweak or two to update it to current DMD.  You'll need to change any code 
that use RGBColour.ref to use RGBColour.value instead.

It even compiles under DMD 2.x; however, it's still experimental in this 
respect.

http://pr.stewartsplace.org.uk/d/sdwf/

In particular, where to return char[] and where to return const(char)[] 
aren't quite fully decided.  See the thread "[Design] return char[] or 
string?" on d.D.learn.
http://tinyurl.com/38kylh

Stewart.