Insteon: Pass Message Clearing Decision to on_read_write_aldb

on_read_write_aldb now returns a 1/0 corresponding to whether the current message should be cleared.

When a bad message arrived, on_read_write_aldb attempted to requeue the message that was currently pending.  However, _process_message did not clear the pending message until after this routine was run.  As a result, a new message was not queued because it was duplicative, but then the current message was cleared.  This resulted in stalling the message queue.

Fixes bug #258
Insteon: Don't Clear Queue on Unhandled Mem_Action

Missed one instance in which the queued message should not be cleared.
Should not be cleared on an unhandled mem action either.

Further Fix to #258
Insteon: Add Success_Callback to Message Object

Success_callback is eval'd when the ACK for the message is received.
- Note: There are so many callbacks all over the place within the code, it might be nice to condense as many as possible into this routine.
Insteon: Add routine for Linking I2CS devices

The routine requires a few steps to complete
Insteon: Add Callback to Routines used by Link to I2CS

Each routine needs to have success and failure callback parameters
Insteon: Convert Link_to_Interface to Handle i2cs or non-i2cs devices

The routine first checks to see if the device will respond to a get_engine_version request.
If any ACK is received the routine continues as normal.  In this case even if the device is an I2CS, the device must already have link entries as it responds to the PLM.
If a NAK is received, it is assumes that this device is an i2cs and the link_to_interface_i2cs routine is called.
Insteon: Linking Mode Requires an ACK, Don't Clear Messages on All_Link_Complete
Insteon_I2CS_Linking: Clear Active Message When PLM Reports All-Linking-Complete

Rather than clear the linking mode command when the device ACKs, wait to clear the message until the PLM reports the linking success.
Insteon_I2CS_Linking: Move Success Callback Eval to BaseInterface

This allows for per device _process_message subs to exist without needing to reproduce all of the eval code.
Insteon_i2CS_Linking: Add Success_Callback to Extended Messages
Change Referenced to Web Cache Directory to html_alias_cache

html_alias_cache is defined as data_dir/cache by default.  Most installations will only require the data_dir to be defined, only those with special installations would need the cache dir to be outside the data_dir.

Closes #229
Insteon_i2CS_Linking: Clear Awaiting Ack Flag on All-Link-Complete

If flag not cleared, all messages to that device will stall
Insteon: Reset ALDB Scan Time on Completed Successful Scan Only

Previously we reset when we started a scan

Now we reset when a scan has completed successfully and each time when the device tells us that the ALDB Delta has not changed.

We also reset if serial query_aldb_delta requests are received in less than 2 seconds.  This allows for sequentail aldb actions without slowing down to send a request to the device for its ALDB Delta when it is unlikely that it changed.
Merge pull request #276 from krkeegan/insteon_aldb_scantime

Insteon: Reset ALDB Scan Time on Completed Successful Scan Only
Insteon: Add Delete All-Link Record Descriptor

Minor addition.
Insteon_RemoteLinc: Remove Arcane Reference to is_battery_low

Routine was removed in favor of child battery object
Merge pull request #278 from krkeegan/insteon_remotelinc

Insteon_RemoteLinc: Remove Arcane Reference to is_battery_low
Merge pull request #277 from krkeegan/insteon_decoder

Insteon: Add Delete All-Link Record Descriptor
Merge pull request #265 from krkeegan/insteon_i2cs_linking

Insteon:  Add Link_to_Interface for I2CS Devices
Merge pull request #260 from krkeegan/fix_issue_258

Insteon: Pass Message Clearing Decision to on_read_write_aldb