Terminate early when no terms left in the suggest string.

Closes #2817
Move applying alias filter to ContextSearch#preProcess()
Date math in query_string caches now()
fixes #2808
remove the field settings for query parser cache, not really relevant
Merge commit '473473e86762b72c13d435a23fb4a8330c692487'

# By Shay Banon (2) and others
# Via Shay Banon
* commit '473473e86762b72c13d435a23fb4a8330c692487':
  remove the field settings for query parser cache, not really relevant
  Date math in query_string caches now() fixes #2808
  Move applying alias filter to ContextSearch#preProcess()
  Terminate early when no terms left in the suggest string.