Support for GROUP BY and ORDER BY for queries

[dhotson]

Also, added support for ORDER BY in collections.

[dhotson]

Oops, forgot to commit test cases. One minute..

[lox]

Have you seen the work that @bjornpost did in #26?

[lox]

Think this is a simple and straight-forward solution for the moment.

[dhotson]

Some examples of usage:

Adding GROUP BY and ORDER BY clauses to queries:

$query = new \Pheasant\Query\Query();
$query->select('*')->from('blah')->groupBy('blahid')->orderBy('blahid desc');

Ordering Collections:

Blah::find()->orderBy('timecreated asc')