Remove the metric_fu quality dependency
Remove the metric_fu quality dependency

We've found too many issues with having metric_fu
and its minions as our development dependency and
it's easier to just drop them then to figure out how
to fix it. If one wants to run code quality checks
on the codebase it's obviously still possible but
you need to handle deps installation on your own.

What were the problems?

1)
with metric_fu along with roodi etc in the gemfile
bundling takes forever (ok, it takes about 40-60
minutes)

2)
if we leave only metric_fu as the dep (which depends
on roodi etc. anyway) we will get latest versions
of the gems which unfortunatelly results with a weird
error when running semipublic specs so we need to
pin the versions which gets us back to the problem #1
datamapper/dm-mysql-adapter