delete a few rules for non-existant tables

These rules are unecessary, either because the table doesn't
exist or look better without it.
buttons should look like button-default by default
use extend, not mixins for creating form-group row

Slightly less CSS, slightly more self-documenting
remove hardcoded color for login page details

This hardcode's #111 for a couple of things on the login page
which messes with bootswatches. I was going to move it to
the custom bootswatch but I'm not sure it's correct. It seems to be
making a link not look like a link, but I'm not sure why.

And the label tex should already inheret the correct color.
run grunt less over latest changes
Merge pull request #152 from ds125v/minor_tweaks

Minor tweaks