Renaming field is_7_to_13 to juvenile_age
Fixes #315

- Change "Is 7 to 13" checkbox to radio buttons
- Modify some logic on survey_main to use new checkbox name
- Modify JS to validate new radio buttons
- Add age into AGJUVENILE emails so we know which consent form to send them
Fixing tabindex on radio button
Remove juvenile age from subject line

The radio buttons' values are now simple english phrases that are included
in the body of the email.
Merge branch 'master' of https://github.com/qiime/qiime_web_app into i315

Conflicts:
	www/americangut/new_participant.psp
Merge pull request #458 from adamrp/i315

I315