Insteon: Relocate local_onlevel, local_ramprate, and update_local_properties

Moved to the more appropriate DimmableLight class
Insteon: Supplement update_local_properties to handle I2 devices

- Added necessary messages.
- Relocated definition of extended_get_set to BaseObject as multiple objects use this
- Added some better descriptions of the functions
Merge branch 'fix_issue_237' into running_hopcount