Crash if uniform_bin MaxSize is not greater than MinSize

If you try to run with {value_generator, {uniform_bin, 5000000, 5000000}}.

The following happens:

13:46:56.762 [debug] Driver basho_bench_driver_riakc_pb crashed: {function_clause,[{random,uniform,[0],[{file,"random.erl"},{line,111}]},{basho_bench_valgen,'-new/2-fun-5-',3,[{file,"src/basho_bench_valgen.erl"},{line,47}]},{basho_bench_driver_riakc_pb,run,4,[{file,"src/basho_bench_driver_riakc_pb.erl"},{line,170}]},{basho_bench_worker,worker_next_op2,2,[{file,"src/basho_bench_worker.erl"},{line,233}]},{basho_bench_worker,worker_next_op,1,[{file,"src/basho_bench_worker.erl"},{line,239}]},{basho_bench_worker,rate_worker_run_loop,2,[{file,"src/basho_bench_worker.erl"},{line,330}]}]}
13:46:56.762 [error] Worker <0.111.0> exited with crash

Suggest validating it before execution and warning end user