Revert "Allow string or array Cursor::hint() argument"

This reverts commit acf548cb4e7e4a6d04587513356dbefc5c9cd6b9.
Merge pull request #163 from doctrine/1.0.x-hint

Revert "Allow string or array Cursor::hint() argument"
Changelog entry for 1.0.7
Merge branch '1.0.x'

Conflicts:
	lib/Doctrine/MongoDB/Cursor.php
	lib/Doctrine/MongoDB/LoggableCursor.php