Highlight that `update!` comes from gem
Add helpers to facilitate js/non-js testing

Prior art from Smart Answers:
https://github.com/alphagov/smart-answers/blob/master/test/integration_t
est_helper.rb#L59-L84
Breakdown business support tests into parts

Refactor into smaller tests that test individual features
Move javascript test helpers to IntegrationTest

Test helpers are useful for both IntegrationTest and
JavascriptIntegrationTest classes.

* Add helper to check whether test is using javascript
* Switch action within save_edition based on this (default driver has
no trigger action)
Test editing of business support with & without js
Allow saving of business support without js

When validating business support editions it expects areas to be an
array. Submitting without JS gives a comma separated string.

* If a string is submitted, coerce it into an array
Simplify business support areas js

Now non-js submission works we can avoid using a hidden input for the
select2.

* Use the text area for the select2 field
* Submit data as a comma separated string rather than a rails array
IDs are hyphenated strings, not numbers

Be clearer about the form area IDs take in the Javascript spec
Don't change the form label with JS

A custom label within the markup works fine
Remove areas prefill variable
Hide 'All of' checkboxes when js disabled

These boxes are helpers that fill in the regions for the UK or England
when checked, but they need JS to work.
Merge pull request #339 from alphagov/non-js-business-support

Allow editing of business support editions without javascript