- to compensate for the slower parser, optimised it a little
- change basic_string to fray, a refcounted immutable string
- add 'xml' tool, prints the parser tree in XML
- rewrote parser to use boost.spirit instead of a hand-written parser
- refactored request loading into 'request' object
- added 'expr', a command-line tool to test the new parser
- some performance fixes for affunctions