Bug 825374 - [email] UI regression on compose card; address input boxes cut off text, appear to resize based on amount of text typed in them.

Also includes a fix for the lack of a comma key with type=email
https://bugzilla.mozilla.org/show_bug.cgi?id=825812
Merge pull request #7252 from asutherland/fix-compose-css-regression

Bug 825374 - [email] UI regression on compose card; address input boxes cut off text, appear to resize based on amount of text typed in them. r=schung, a=blocking-basecamp