Update of the softphone librairy to work with asterisk (Digest Auth updated)

[pascal-pro]

Update the struct of Softphone and update the Digest Auth part to simplify use.
More info here: https://en.wikipedia.org/wiki/Digest_access_authentication

[Sean-Der]

Hey @pascal-ace

Do you mind rebasing? Since you are behind master we have a bunch of conflicts.

How is the project going with these changes! Everything working, any bugs?

[pascal-pro]

I will try to make a separate branch, but normally, the conflicts are only in the SIP example, everything else is to refuse. (The hand has also changed its name)
This is a current update, to make it work with asterisk. For the moment, it still works with Freeswitch, but still not with asterisk.
The softphone folder has been updated to add / change / clean up the library and make it more readable and clearer.

[pascal-pro]

Maybe you prefer that I host the softphone on my github, and that I make a version, so that the example always works, and I make you PR every time I change the lib or the structures?

[saiteja-v]

These changes seems to have an issue in register.go
Code exits from the main and socket is closed before the track is saved. The switch statement in register and no context used certainly looks like an issue.