Feature/allow separate and parameters & Fix Relation with Or

[lloy0076]

There are no tests for this (but it does work) and this PR is more for discussion.

This address issue #42 by allowing users to append __and and __or; all the __and will group together and the __ors are self explanatory. So you can do:

• url?columnOne__and=1&columnTwo__and&columnThree__or

It also fixes #38 which is a duplicate of PR #39 but I'm not sure #39 works.

[lloy0076]

Hmmmm...I'll look at the test that failed.

Anyone know, though, why the external coverage from external is not available, or no code coverage driver is available? Is that because of the failed unit test?

[lloy0076]

Bah!

I'll need to fiddle all the tests because I just realised that this change causes all the queries to look like they're nested and so a bunch of assertions are wrong.

So my diagnosis is:

1. The tests are wrong;
2. The code is correct.

I say this on the basis I have this in production, as such :)