Allow socket path to be customized

[michaelcadilhac]

When using multiview -s, a socket is used for communication. Its path is described as:

var socketPath = path.join(__dirname, '/' + channel + '.sock');

If I understand correctly, __dirname is the path of the library, wherever it is installed. When multiview is installed with a package manager (e.g., on the AUR) it is installed in privileged directory, and the file failed to be created (with no error!).

Hence feature request: Allow for that dirname to be customized, and for an error message to be spat out if the file can't be created.