removed some rubbish
hopefully better memory stuff for parser

better memory stuff for parser

This is needed as while expat has XML_{S,G}etBase, they maybe nested and expat doesn't support a stack for this.

altered handlers' signatures accordingly

A large rewrite of Robs dreadful code, he just didn't understand what he was doing. I think we now call blixem correctly.

Add a redraw function to force redisplay of window. Add feature redraw func to redraw new context in existing window. Add function to blank a window.

Remove redundant routines now in zmapWindowDraw.c, add code to handle when we redraw features but do not change the scrolled region (e.g. for reverse complement).