[rss] Fix default value for fg/bg. Fix #636
[search] Don't record last seen url if feature not enabled

Closes #644
[db] Fix an injection issue in update

There's still plenty of potential for problems with this. Stuff like
this is why #194 needs to happen. Related to #645.
[github] Give an error when using .addtrace with no args

Closes #649
[translate] Check to ensure .tr has an argument

Closes #651
Merge pull request #637 from oklahomer/hotfix/rss_default_colour

[rss] Fix default value for fg/bg. Fix #636
Merge remote-tracking branch 'upstream/master'

Conflicts:
	willie/modules/github.py
	willie/modules/rss.py
	willie/modules/search.py
	willie/modules/translate.py