Working on Regex

Noting [this issue](https://github.com/smtech/smcanvas-ics-sync/issues/8), and [this comment](http://php.net/manual/en/function.addslashes.php#47219) and some foolishness in my own code, trying to get regex filtering working again.

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>