Remove unused pages and controllers

The style guide is no longer used, and neither is the documents controller.  This commit removes those files and updates the routes file.
Data segregation: Only display listing pages if supplier ID matches

If a supplier with a valid SSP login cookie tries to hack the URL to view another supplier's product details/summary page they should not be able to see them.
Data segregation: Only save listing pages if supplier ID matches

If a supplier with a valid SSP login cookie tries to spoof a POST request to overwrite another supplier's product details they should not be able to.
Merge remote-tracking branch 'origin/master' into ensure-data-segregation

Conflicts:
	app/controllers/Page1.java
	app/controllers/Page10.java
	app/controllers/Page11.java
	app/controllers/Page12.java
	app/controllers/Page13.java
	app/controllers/Page14.java
	app/controllers/Page15.java
	app/controllers/Page16.java
	app/controllers/Page17.java
	app/controllers/Page18.java
	app/controllers/Page19.java
	app/controllers/Page2.java
	app/controllers/Page20.java
	app/controllers/Page21.java
	app/controllers/Page22.java
	app/controllers/Page23.java
	app/controllers/Page24.java
	app/controllers/Page25.java
	app/controllers/Page26.java
	app/controllers/Page27.java
	app/controllers/Page28.java
	app/controllers/Page29.java
	app/controllers/Page3.java
	app/controllers/Page30.java
	app/controllers/Page31.java
	app/controllers/Page32.java
	app/controllers/Page33.java
	app/controllers/Page34.java
	app/controllers/Page35.java
	app/controllers/Page36.java
	app/controllers/Page37.java
	app/controllers/Page38.java
	app/controllers/Page39.java
	app/controllers/Page4.java
	app/controllers/Page40.java
	app/controllers/Page5.java
	app/controllers/Page6.java
	app/controllers/Page7.java
	app/controllers/Page8.java
	app/controllers/Page9.java
Display all error messages on all pages

Custom error messages were not being shown on all pages.

This introduces a new method on the Fixtures class that retrieves an
error message. It first checks if the message is a key in the
content.properties file. If not, it returns the message as is. This
allows custom messages to be defined in the controller where necesarry.
This was already being done but they weren't being displayed in the
frontend.

On questions with multiple text values (eg. features and benefits), only
one error is shown per question rather than one per question value.
Because of this the validation message has to be keyed by the question
key rather than the value key.
Update content to include latest changes
Add validation masthead on first two questions
Increase assurance max size to 60 characters

The largest assurance answer is now 55 characters long. This gives us a
small amount of buffer.
Display error messages on pages 14 and 24
Couple of redirects that should have been taken out before
Do not accept percent below 0 on q24
Merge pull request #127 from alphagov/ensure-data-segregation

Ensure data segregation
Merge pull request #125 from alphagov/display-validation-messages

Display all error messages on all pages
Update submodule
Auto-tick 'completed', allow untick and save

Bugs fixed by this commit
- The 'this service is completed checkbox' did not persist its
  value to the page
- Unticking it and resaving the service had no effect—the service
  stayed in completed
Merge pull request #133 from alphagov/completed-service-checkbox

Auto-tick 'completed', allow untick and save
Merge remote-tracking branch 'origin/master' into fix-return-to-summary

Conflicts:
	app/controllers/Page4.java
	app/controllers/Page5.java