On the fly modification of the running printer threads

[tperale]

On the fly modificaiton of the "printer" threads require a rework of the program structure. All the messages will be sent to the "main" program thread and the print messages will then be dispatched to the correct "printer" thread with the help of a "Queue". The queue will help to make the difference between a print message or a control message to change the behaviour of the printer thread (changing address, port, destination, format, etc ...)

In the end it will allow:

• Add or remove printer threads during the execution of the program through instruction sent to victoria program.
• Change the channel name, channel receiver.

[tperale]

This issue need to be solved before the implementation of Sprtch/huron#35 can start.

[tperale]

Should the channel still exist in the end ? In the end all we need is the name of the destination printer, the channel introduces some sort of overhead that is not obvious to the user.