Insteon: Add Sync_All_Links Routine for Multigroup items; Add MultigroupDevice Package

Added a package called MutigroupDevice in BaseInsteon.pm.  The purpose of this package is to contain routines specific to all multigroup devices.

Added Sync_All_links routines to MultigroupDevice.  The routine will sync all links between any group on the device.  Useful for KeyPadLincs and RemoteLincs and such.

Fixes #85
Insteon: Add Sync All Links Voice Command to Multigroup Devices
Insteon: Multigroup Sync All Links to Scan Root Object

Not sure why I omitted this before.
Merge pull request #301 from krkeegan/fix_issue_85

Insteon: Add Sync_All_Links Routine for Multigroup items; Add MultigroupDevice Package