Added mode parameter to WEEK

I've added the mode parameter to the WEEK mysql function

http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_week
Merge pull request #115 from alex88/patch-1

Added mode parameter to WEEK
Remove merge conflict remnant from readme
Added REGEXP and NOT REGEXP operators
Added REGEXP function
Merge branch 'master' of github.com:cnelissen/DoctrineExtensions

Conflicts:
	lib/DoctrineExtensions/Query/Mysql/Regexp.php
Merge pull request #120 from cnelissen/master

REGEXP Function
Merge pull request #118 from terite/patch-1

Remove merge conflict remnant from readme
Fixed DATE_ADD syntax to be compatible with Doctrine syntax
Update DateAdd.php

add QueryException namespace