Initial update for Insteon 2412N

Added initial code to allow Insteon PLM to communicate with an ethernet
connected PLM as well as serial.
Remove hard-coded Perl path that causes email fetching to fail.

When a user installs a local Perl version to run MisterHouse
under instead of using the system-provided Perl, then the
hardcoded Perl path at the shebang in get_email causes the
module search path to be incorrect. /usr/bin/env perl
properly solves this issue.
Update download.pod for v3.0, fix update_docs

Create output directory in update_docs if it doesn't exist
Remove docs/download.html from repository; auto generated
Update docs/download.pod for v3.0
Fix http links in some files
Remove remnants of aws_weather from mh.ini
Add warning if Insteon_PLM_serial_port is missing from ini file
Fix data3 for responder records to PLM scene

Fix Issue #327. This fix also applies when a responder is I2CS and the controller
is I1. Added logging for the data3 value. Aligned the logging levels between
sync_links() and update_link().
Insteon_Thermo: Add Derive_Link_State, Fix Typos, Check State Before Setting Cooling

Need custom derive_link_state to allow for custom link states.
Move data3 logic into the Insteon device objects

Add link_data3() function at the device level
Modify aldb functions that set or check data3 to use the new function
Add grotesque, level 5 logging that should be removed later
Added missing link_data3() for Insteon_PLM
Add call to link_data3 in Insteon_PLM::has_link
Remove grotesque debug logging
Merge pull request #328 from mstovenour/fix_responder_data3

Move aldb link data3 logic into Insteon objects

Fix data3 for responder records to PLM scene
Add flexibility to how aldb link data3 values are specified; each Insteon device can specify a unique behavior
Update so that most Insteon objects use group 00 for endpoint 1 responder links (was 01 for all I2CS devices)
Override logic for Insteon::SwitchLincRelay to use group 01 for endpoint 1 responder links for I2CS devices
Note:  Might consider doing the same for data1 and data2 in a future update
Merge pull request #331 from mstovenour/fix_documentation

Update download.pod for v3.0, fix update_docs
Merge pull request #332 from mstovenour/fix_ini_cleanup

Fix ini cleanup
Fix Linux blank line handling for PLMTerminal
Merge pull request #334 from mstovenour/fix_PLMTerm_newline

Fix Linux blank line handling for PLMTerminal
Merge pull request #338 from krkeegan/Insteon_Thermo_Fix

Insteon_Thermo: Add Derive_Link_State, Fix Typos, Check State Before Setting Cooling
Fix mailing list location in Ia5

Partially fixes hollie/misterhouse#339
Fix Target for Links on docs/maillist.html

Partially fixes hollie/misterhouse#339
Delete reference to defunk IRC Channel

hollie/misterhouse#339