Added havingRaw() and orHavingRaw()
I'm not sure if this is the perfect implementation, but it does what I need at the tests are green.
Merge branch 'master' of git://github.com/laravel/framework

Conflicts:
	tests/Database/DatabaseQueryBuilderTest.php
Fixed a docblock.
Merge pull request #493 from philsturgeon/feature/having-raw

Added havingRaw() and orHavingRaw()