New features:
* Introduce Object Sizes (GH-808).
* Add ListDecoder for verifying a config option that expects list values
(GH-807).
Enhancements:
* Bump HBase to 1.0.3 (GH-822).
* Change MockFlags to be more like the real FlagValues (GH-812).
* Rename test_flag_util.py and add FlagDictSubstitution tests (GH-811).
* Create BenchmarkConfigSpec to aggregate benchmark input
checking (GH-810).
* Remove flag proxy objects (GH-802).
Bugfixes and maintenance updates:
* Fix sample iperf sample (GH-801).
* FixIntDecoder and FloatDecoder behavior when min=0 or max=0 (GH-800).
