Simplify form generation code

[david-a-wheeler]

There's a lot of repetition in the Ruby code generating the Rails - simply that (e.g., a separate method for generating the radio buttons).

[david-a-wheeler]

This is important for making the other changes much easier.

[david-a-wheeler]

There are various ways to implement this in Ruby on Rails, including partial templates and custom helpers.

Since the repeated code is mostly HTML, I think partial templates are the better option in this case. Filenames of partials begin with "_", and get invoked using this kind of format:

<%= render(:partial => "partial_name", :locals => {:f => f}) %>

[david-a-wheeler]

Resolved in commit e364e04