Add no_hop_increase flag logic, set flag when message ignored

Cleaned up coding formatting surrounding NACK message handling in BaseInsteon _process_message.

Removed superlous Hop Count Increased logging messages.

Added no_hop_increase flag to BaseMessage object.  When defined, this flag will prevent the hop count from increasing when a message is resent.  This flag should be set when the need to resend the message is not as a result of a failure of the device to receive the message.

no_hop_increase flag is set to the following situations:
- NACK received from a device
- Incorrect cmd1 code for peek or set_address_msb messages
- Cmd1 not a valid command messages
- PLM ACK mismatch
- PLM extremely busy

I am sure there are more instances in which the flag should be set.
Merge pull request #99 from krkeegan/hop_tracking

Insteon: Don't Increase Hop Count When Messages are Received but Ignorred