removed preg_replace with /e modifier

switched from using preg_replace with /e as it's deprecated in 5.5 and
not supported in some environments;
while an anonymous function would work, by using create_function we can
stay 5.2 compatible
removed the /e modifier, left by accident
Merge pull request #123 from caseysoftware/preg-refactor-e

Removed the preg_replace /e modifier in favor of using create_function