Initial update for Insteon 2412N

Added initial code to allow Insteon PLM to communicate with an ethernet
connected PLM as well as serial.
Merge remote-tracking branch 'andth/InsteonIP' into InsteonIP

Conflicts:
	lib/Insteon_PLM.pm
InsteonIP: Attempt to Avoid Errors When Messages are Sent by Insteon IP Hub

Messages are going to come in that MH will potentially see as acknowledging commands that it never sent.  These changes attempt to avoid failures that might appear.

I don't have a hub to test this on, so these are just guesses.
Merge branch 'fix_insteon_has_link' into InsteonIP
Merge branch 'fix_insteon_has_link' into InsteonIP
Merge branch 'fix_insteon_has_link' into InsteonIP
InsteonIP:  Add documentation

This completes the requirements for merging this into master.
Merge pull request #375 from krkeegan/InsteonIP

Add Support for IP Enabled Insteon Access Points