[bug 931189] Add character counter to feedback form

This (re)adds the character counter to the normal feedback form. This
doesn't prevent users from submitting the form--it just indicates how
many characters are acceptable, when the user is getting close to the
limit and when the user is over the limit.
[bug 931189] Add character counter to mobile feedback form

This adds a character counter to the mobile feedback form. This doesn't
prevent users from submitting the form--it just indicates how many
characters are acceptable, when the user is getting close to the limit
and when the user is over the limit.

Also, I moved part of the privacy text upwards so it's right under the
description. This is not a change that requires l10n work. It is a
change that the Privacy folks suggested in bug 934721 for the other
feedback form.
[bug 931189] Add character counter to Firefox OS feedback form

Adds a character counter to the Firefox OS feedback form. This doesn't
prevent users from submitting the form--it just indicates how many
characters are acceptable, when the user is getting close to the limit
and when the user is over the limit.