Query builder - dynamic "where" clauses

Being an avid believer of Pull Request or STFU, I agreed with issue #241 and how it was a nice feature of Laravel 3.

I believe that dynamic where clauses, e.g. `User::whereFirstNameOrAge('Ben', 21)->first()` can sometimes be a nicer way than putting `User::where('first_name', '=', 'Ben')->orWhere('age', '=', 21)->first()`. For this reason, I've added the functionality back in for dynamic "where" clauses into the query builder.

*I also noticed that Sublime has removed a couple of rogue spaces from the end of lines which have been added in. Enjoy.*

 \- Ben