OpenTSDB 2.4.0 RC2

• Version 2.4.0 RC2 (2017-10-08)

Noteworthy Changes:

• Modify the RPC handler plugin system so that it parses only the first part of
  the URI instead of the entire path. Now plugins can implement sub-paths.
• Return the HTML 5 doctype for built-in UI pages
• Add an optional byte and/or data point limit to the amount of data fetched
  from storage. This allows admins to prevent OOMing TSDs due to massive queries.
• Allow a start time via config when enabling the date tiered compaction in HBase
• Provide the option of using an LRU for caching UIDs to avoid OOMing writers and
  readers with too many strings
• Optionally avoid writing to the forward or reverse UID maps when a specific TSD
  operational mode is enabled to avoid wasting memory on maps that will never be
  used.

Bug Fixes:

• Roll back UTF8 issue with UIDs in RC1 wherein the stored bytes weren't converting
  properly and vice-versa. We'll have to work on full UTF8 support in 3.x
• Fix a build issue for Javacc
• Add Kryo as a dependency to the fat jar
• Javadoc fixes
• Fix an issue with calendar aligned downsampling by seeking to the start time of
  the query when the zone-aligned timestamp may be earlier than the query start time
• Add the missing QueryLimitOverride to the makefile
• Fix compatibility with Bigtable for 2.4
• Enable standard read-only APIs when the TSD is in write only mode