Revert "adapter: remove deprecated ListDevices() method"

This reverts commit 5a4951dae68e56b24419a4f8b41e34537af0b698.
Revert "plugins: remove unmaintained plugins"

This reverts commit dd3f4ca901cc92f076c371db52aad7d59849f6da.

NOTE: this reverts only Maemo6 plugin.
debian: Add patch for D-Bus policy

Reinsert patch in debian directory to allow UI communicates with BlueZ
daemon.
proximity: Remove 5 second Immediate Alert timeout

This timeout is not expected by the Proximity profile, and sometimes
cause too short alerts.
proximity: Export TX Power as device property

This allows to calculate path loss externally.
debian: Update package version and changelog