3cx v18 support

[vgavgavga]

since 3cx updated their softphone to v18 and there is no C:\ProgramData\3CXPhone for Windows\PhoneApp\3CXClickToCall.exe anymore

[WoosterInitiative]

Ummm, I didn't realize anyone even knew this existed. Also, I no longer work for the company using 3CX so I don't have a way to test this.

Feel free to do a pull request if you'd like to modify that functionality.