An improved webphone for the Vicidial Call Center Suite.

This code is a fork from the original code by Michael Cargile (https://github.com/vicimikec/ViciPhone), and as such contains the following enhancements:

• Uses SIPJS version 0.15.11 as of 2021-02-27, supporting all modern browsers.
• Allows SIPJS to be downloaded from a CDN as minified version.
• Support for multiple translations. Currently adds spanish and german support, but is open for more.
• Can call the agent instantly after the webphone has loaded (like a regular softphone), saving time and human error.
• Added a call timer to provide visual feedback when agent is inside a call
• Can display alpha characters inside DTMF buttons for easier typing inside IVRs

Several other improvements can be read in the commits logfile.

To use it on Vicidial, you must set up a webrtc template as follows:

type=friend
host=dynamic
encryption=yes
icesupport=yes
directmedia=no
transport=wss
dtlsenable=yes
dtlsverify=no
dtlscertfile=/PATH/TO/YOUR/SSL/CERT
dtlsprivatekey=/PATH/TO/YOU/SSL/KEY
dtlssetup=actpass
rtcp_mux=yes

The field rtcp_mux is the most important change since Viciphone 1.0, so that is a must.