Migrate RingMediaChannel to use TpBaseChannel

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>
Generate required Call interfaces

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>
Refactored to use ratified telepathy call spec.

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>
Update to new tp base classes and interfaces

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>
Fixed some issues with old call interface

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>
More interface reverts to keep tp-ring working.

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>
Updated media manager interface property spec.

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>