Upgrade to elasticsearch 0.20.4 and zookeeper 3.3.6

Fixes #12
Merge remote-tracking branch 'imotov/upgrade-to-es-0.20.4'
Release 0.20.0
Upgrade to elasticsearch 0.90.0
Merge remote-tracking branch 'gstarnberger/upgrade_to_0.90'
update readme
update readme for new install
bump to snapshot
Updates compatibility table.
initial try to support v0.90.11
update to v0.90.12
Release 0.90.1