LV2 and Drobillad SVN repository changes

I have changed the layout of the LV2 repository and my LAD repository to no longer use externals for build system things (namely autowaf, which is now bundled in a custom waf script).

SVN does not deal well with anything changing about externals, so I highly recommend you delete your tree entirely and make a fresh checkout. If you don't do this, and have problems, I don't want to hear about them :)