Add better threading suport to allow changing source ports or multiple hosts

[aseques]

This PR contains two changes:

• In one commit there's refactor of the threading part to allow improved functionality (having the PBX change the source port does not break the communication, and you could use two PBX to send data at the same time.
• The other commit requires a new field on the database table so it will store the source host for every communication, improving usage when receiving data from multiple pbx