Register uppercase as an exposed ES token filter.

Just follow "lowercase" token filter example and register "uppercase" token filter as an exposed token filter. This will not, by itself, test whether ES is correctly handling "uppercase" TF; this is more of a "code as documentation" fix.
Do not throw execption on no available nodes when listing benchmarks.

Changed behavior to not throw an exception on a status request
when there are no available benchmark nodes.

Closes #6146
Upgrade to Lucene 4.8.1

This commit upgrades to the latest Lucene 4.8.1 release including the
following bugfixes:

 * An IndexThrottle now kicks in when merges start falling behind
   limiting index threads to 1 until merges caught up. Closes #6066
 * RateLimiter now kicks in at the configured rate where previously
   the limiter was limiting at ~8MB/sec almost all the time. Closes #6018
Added Version [1.3.0]
Remove obsolet ASF repository Lucene 4.8.1 is on maven central
CharArraySet doesn't know how to lookup the original string
in an ImmutableList.

Closes #6237