Input validation on form fields (e.g., to prevent insertion of zero-width space characters).

[kfogel]

Invalid user-entered data has caused us problems before. We should perform input validation on form fields where possible.

[kfogel]

Besides the obvious field from issue #232, we should do input validation in any field that takes one or more email addresses and separates them with commas when there are multiple addresses. For example, on the "Scheduler dispatch export recipient" field in the same chapter, there was a single email address followed by a comma.

@bnazari and I agreed that that comma should be removed, and he did so, but it should never have been there in the first place. Note that no post-input code strips it out, either: on the NCCR administrative view page, the comma was appearing at the end the email address for that field in the collective "Config" value, until we removed it.