Added checkstyle using wildfly-checkstyle-config
set id for the single data point
iniiial commit for metrics_idx table

metrics_idx is a custom index that will be used for querying metrics. The
metrics console app display all the metrics in the side bar. It will eventually
query metrics_idx. The table is now also used for the (optional) metric
creation which ensures that metric ids are unique.
Merge pull request #69 from ppalaga/141124-wf-checkstyle

Added checkstyle using wildfly-checkstyle-config
Fix checkstyle violations and make checkstyle obligatory
add endpoints for fetching metrics (without the data)

The following requests,

GET /rhq-metrics/metrics?type=num
GET /rhq-metrics/metrics?type=avail

query the metrics_idx table. We update metrics_idx whenever we insert metrics
and when a metric is explicitly created. I need to update the methods for
adding/removing meta data so that they also update metrics_idx.

This commit also switches to Jackson 2 as the json provider. I have been
trying to figure out how to suppress from output fields whose values are
null or empty. I was able to get it working with Jackson 2. We probably
want to be using Jackson 2 anyway.
removing some unnecessary classes

Doing a bit of clean up and removing/combining some classes used for json
responses. There is more, similar clean up that can be done. I will tackle it
in a subsequent commit. More test coverage is needed first though.
Merge pull request #70 from ppalaga/141126-checkstyle-violations

Fix checkstyle violations and make checkstyle obligatory
Make test classes to be covered by checkstyle
Merge pull request #71 from ppalaga/141127-test-classes-checkstyle

Make test classes to be covered by checkstyle