And control the filter using the newly-created FilterButtons class. This
lets us hide completely skipped tests by default, since those are mostly
noise. I also add some custom icons used by the buttons to indicate
passed, failed, or skipped tests.
Signed-off-by: Anna Schumaker <anna@nowheycreamery.com>
I install to /usr/local by default, but this can be overridden by
setting PREFIX when running `make`
Signed-off-by: Anna Schumaker <anna@nowheycreamery.com>