fix daemon continually rebuilding the site

With our change to file stores to always use absolute paths
(bff432b118983ec0bf3a6c9571415c1c142b63a4 fixing #172), our
prepending the cwd was incorrectly doubling the path, making us ignore
the wrong build directory.

With Path::Tiny, I need to remember to not use all the other things I
regularly use, like Cwd.

Mac::FSEvents provides an IGNORE_SELF, but it did not seem to work in
this case. I need to investigate why later...
fix test failure because config not found

The dist does not include a site.yml in the root directory, so we need
to chdir to test the default config finding.