process deleted index events on a node even if it has no local FS
this will not happen now, but in the future, if data nodes will only be in memory (including translog and such), then we need to fire the deleted events
Improved test

- checking routing table taken from same (up-to-date) cluster state
- added @Slow annotation
- forced cluster reroute when needed
- changed order of assertions so that if it fails again it's easier to understand why
Added prefix suggestions based on AnalyzingSuggester

This commit introduces near realtime suggestions. For more information about
its usage refer to github issue #3376

From the implementation point of view, a custom AnalyzingSuggester is used
in combination with a custom postingsformat (which is not exposed to the user
anywhere for him to use).