Split out the common bits from the client bits:

- Move as much of mw into src/client/ as possible
- Make sure everything that mwserv and webclient require is in src/
- Build a libmw.a from src/*.o to make linking easier
- Rejig and simplify some Makefile rules

This should help to make it clear which bits of code are shared and which are specific to the UI. We should avoid putting any user interface stuff into libmw.a as a rule.

TODO:
- Improve some file names (e.g. sqlite.{c,h} is a silly name)
- Fix building the utils
- Add sensible svn:ignores to src/client