Added PREG constants to the list of predefined constants.

The full list of PREG constants can be found at <http://php.net/manual/en/pcre.constants.php>.

Signed-off-by: Eric James Michael Ritz <lobbyjones@gmail.com>
Removed unused defconst.

Signed-off-by: Eric James Michael Ritz <lobbyjones@gmail.com>
Update php-mode-modified
Merge branch 'github/pr/127'

* github/pr/127:
  Update php-mode-modified
  Removed unused defconst.
  Added PREG constants to the list of predefined constants.