Updated NGF plugin to use profile set ringtone.
Updated NGF plugin to pause stream, instead of stop when call ignored.

Signed-off-by: Tom Swindell <t.swindell@rubyx.co.uk>
Made NGF ringtone plugin handle VOIP call ringtones correctly.

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