Remove absolute paths for srcdir and destdir from ikiwiki.setup.
The content is now built in ./html/. This inspired an update to the
exclude regexp to avoid creating ./html/html/... with repeated builds.
Note that you may qhave to remove ./.ikiwiki/ for the new exclude to
take effect.
Also flesh out .gitignore to ignore built files, disable default git
pull, disable git wrapper generation, and log to the command line.
ikiwiki.setup is now better for generating the wiki to test changes
before committing them.