Tweaks to Commands:
1. Now catches and raises a more descriptive error when the node returns malformed JSON or JSON with non-unicode characters in it.
2. Removed get_txpool_backlog and get_output_distribution because they are actually binary RPC commands in disguise, maybe they can be added later.
3. Improved input validation for start_mining.
4. Catches NOT MINING status in set_log_hash_rate and raises descriptive error.
5. Adds abaility in out_peers and in_peers to set unlimited peers by passing -1 as arg.
6. Make input more intuitive in get_outs.
7. Shortened names of get_all_known_log_levels and get_all_known_log_categories.
8. Other very minor tweaks.
Jeffrey Ryan