filter/date Fallback to en locale + better failure logging and tag_on_failure

Some more improvments to date filter:
* use a fallback parser with english locale when platform default is non-english (LOGSTASH-785)
* improve register error report with invalid pattern (LOGSTASH-1487)
* improve date parsing final failure log (add the config) &  tag_on_failure logic 
(LOGSTASH-777,LOGSTASH-915)