TACHYON-198 Move UserConf usage to use TachyonConf

This PR consist next steps to integrate new configuration work:
-) Remove usage of UserConf
-) Push TachyonConf to Tachyon Hadoop's file system (aka TFS class).
-) Remove UserConf.java from repo.
Yes you are right, we could be more clever by adding common test class that provide TachyonConf that could be passed to the LocalTachyonCluster.

I will take stab at this way.