Fixed migration to objectify 5, fixed concurrency issue on high
concurrency indexing/searching tasks, performance improvements.
Upgrade of maven-source and maven-site plugins.
Upgrade to latest objectify, latest appengine, and lucene to 4.8.1 and
aligned javadoc references.
  Objectify 5.0.3
  appengine-maven-plugin 1.9.7
  Lucene 4.8.1
[maven-release-plugin] prepare release luceneappengine-2.0.1
[maven-release-plugin] prepare for next development iteration