Stop all the children

Anyone who checks the "I am 7-13 years old" box will need to be verified
manually.  Need to test this on webdev to make sure emails are being sent
correctly.
Adding conditional enabling of elements on new_participant
Merge pull request #241 from meganap/agut

Adding conditional enabling of elements on new_participant
Merge pull request #242 from adamrp/juveniles

Stop all the children