Fix email links

All email links were broken before; this PR semi-fixes the issue in that it lays the groundwork for the links to not be broken.

Emails are rendered without knowledge of the application stack or hostname so they need to be configured in the appropriate environment config files.

System administrators (ie Mike Dunlap) will have to configure this host in their own instances of production.rb.

This  PR also removes all (dangerous!) instances of `html_safe`. I'm assuming that whoever put that in thought that it would sanitize the text, but what it actually does is tell Rails *not* to sanitize the text. 

This also needs to be ported to master