Update to allow the use of non numeric dates in the past
Update to allow the use of non numeric dates in the past

A problem was found in that emoncms does not handle non numeric dates in the past elsewhere.  This converts the date to a number of seconds.

chaveiro/emoncms,inverse/emoncms,emoncms/emoncms,inverse/emoncms,inverse/emoncms,chaveiro/emoncms,chaveiro/emoncms,inverse/emoncms,emoncms/emoncms,emoncms/emoncms,emoncms/emoncms,chaveiro/emoncms,emoncms/emoncms