Integration tests assume readonly is false; many fail if readonly is true

[usmanatron]

To reproduce:

• Get a fresh checkout of master
• Edit the test config so that readonly is true (default in the sample file is false)
• Run the tests via "make test"

We should still have all tests passing. Instead, a large number of them fail, as they're dependent on the readonly flag within the test config.

This isn't ideal. The best design in my mind is to define in each test what the expected value of readonly should be. This has the added gain of being able to add readonly specific tests (for example, when readonly is true, the "Add new URL" button should not be showing).

I'm keen to have a go with this, however I think it would be good to nail down what exactly we want to do. Is it reasonable for each test to override "readonly" as required? If a test should pass no matter the value of readonly, how should we manage that cleanly?