OpenVG and ZParse

Copperbox revision 388.

I'm taking a break for HNotate for a bit. I've worked out how to simplify the document building code (principally the TemplateDatatypes module), but that means redoing the parsers again so they handle island parsing better (and don't build the parse tree with continuations). I got rather frustrated with Parsec's lexer handling - not that it isn't capable just that I was probably trying to solve my problem in the wrong way - so I started another parser combinator library ZParse. Applicative and Alternative now encompass much of the work need for basic parsing, so writing the usual combinators was easy, but handling tokens is tricky so maybe I'll go back to Parsec.

For a change I've started on a Haskell binding to OpenVG - the vector graphics API. I've spent the whole day defining constants and I've still got half of the marshallers to do, never mind unmarshalling. As this is a baby step compared to the involved stuff of calling functions through the FFI, it looks like the binding will be a much bigger job than I thought.