Insteon: Set Send Timeout on a Per Device Basis

Allows users to adjust the send timeout on a per device basis.  

$device_>timeout_factor(1.0);

The timeout_factor is multiplied by the preset timeout.  So a setting of 1.0 has no effect, while a setting of 1.1 would increase the default timeout by 10% and a setting of 0.9 would set the timeout to 90% of the default.