Use Maven as build system

* Introduce local repo (./lib-repo) where everything that was required in ./lib
  has been introduced.
* Minor fixes to certain components because of newer dependencies available.
* Use public opentsdb interfaces for interacting with the database and include
  tsdb in ./lib-repo. Included the previous net.opentsdb code from
  https://github.com/brianhks/opentsdb
* Remove lib/ivy completely (in favor of local maven cache).
* Remove dependency to jcmdline (in favor of commons-cli) to reduce the amount
  of jars required in ./lib
* Modify README.md to reflect 'how to do things' and caveats.