Revert 'fat jar' change from #389 on beta branch, already reverted on master, fixes #470

The wiki for the beta branch says:
> Any updates to the master branch (thrift based changes) will be ported forward to the beta-java-driver branch.
But the graph doesn't show any merges so I just cherry-picked this change.  If you prefer to handle it differently, please let me know.  The original "fat jar" change caused two problems:

* Renamed the `astyanax-core` jar to `astyanax-all`, which also changed the artifacts and metadata generated by that subproject, but other subprojects' metadata still referred to `astyanax-core` (#470)
* Caused by default the `astyanax-core.jar` to contain all runtime dependencies -- including multiple logging libraries -- which caused runtime breakage with my downstream project because of the logger inclusions that could not be controlled any longer by transitive dependency management directives (e.g. exclude `commons-logging`).