Fixes datepicker from jumping to 1970 or 2070

When $date is passed from the datepicker as

Fri Jul 04 2014 10:00:00 GMT+1000 (AUS Eastern Standard Time)

The timezone on the end causes $ts to be blank.

Strip the bracketed timezone from date before strtotime()

This seems to fix it in our environment, hopefully it doesnt break it elsewhere!