add waffle.io badge
Merge pull request #83 from waffle-iron/master

waffle.io Badge
Update README.md
Update README.md

Fix travis badge.
Merge branch 'master' into dev

Conflicts:
	README.md
Clean up the settings activity. Because we are targeting sdk > 11, we
can remove a lot of cruft.

Add some preference validation. Add tests for validation. Note: this
only validates uri syntax, not if the hosts actual exist. That will come
later as a button (or something).

Tested:
  ./gradew clean test