[FLINK-1270] [APIs] FS.get() supports relative paths

This closes #224
[FLINK-1095] [clients] Remove '-d' option in info from CliFrontend

This closes #238
[FLINK-1273] [runtime] Add Void type to basic types

Add optional test for external sorting of case classes.
Fix various warnings.
Upgraded HBase addon to HBase 0.98.x and new Tuple APIs