initial commit for retentions_idx table

retentions_idx is a custom index used for query data retentions. This commit
also includes changes to store tenant level data retentions in retentions_idx.
The data retentions are cache in memory at start up.
do not cache tenants

At least for now there is no need to cache all of the tenants. We just need to
cache each tenant's data retention settings.
fix bug for computing ttl on tagged data points

This commit also includes a big reactoring in the tests that verify TTLs. It
removes the Thread.sleep calls which were slowing the tests down considerably.
It also makes the tests more flexible because you can now write the data into
the past in order to simulate an updated TTL. For example, suppose we are using
a TTL of 7 days. If data was written 2 days ago, then the TTL would now be five
days.
store data retention in seconds not hours since C* TTL is specified in seconds
perform necessary data retention writes when creating a metric

When we create a metric where the data retention is specified, we write it to
three places, retentions_idx, metrics_idx, and data tables.
update queries to return data retention
fix compiler error due to minor API change
Merge pull request #87 from rhq-project/data-retention

Add metric level data retention support in core Java API
Moved Influx handler endpoint to "/tenants/{tenantId}/influx/series"
Renamed InfluxSeriesHandler
[PR-52] Build fails on RHEL 6.6.
Original issue is with: https://github.com/imagemin/gifsicle-bin/issues/36
 Tracking down the dependencies gifsicle is used by grunt-contrib-imagemin which  is used my ngmin which gives us app minification. So I just removed everything related to app minification.
Merge pull request #89 from rhq-project/rhel-6.x-build-error

[PR-52] Build fails on RHEL 6.6. Original issue is with: imagemin/gifsicle-bin#36
This is a GLIBC version error used by the native gifsicle package. Tracking down the dependencies gifsicle is used by grunt-contrib-imagemin which is used my ngmin which gives us app minification. So I just removed everything related to app minification.
add support for data retention in REST API
Merge pull request #90 from rhq-project/rest-data-retention

add support for data retention in REST API
Enforce XML indentation using a custom Checkstyle check
Merge pull request #88 from ppalaga/141208-xml-indent

Enforce XML indentation using a custom Checkstyle check
Initial embedded Cassandra work. The code and dependencies now live in the rest-servlet module as a proof of concept.
Move embedded Cassandra specific code into a separate module. The startup is still not working properly, investigating....