Add ability to set custom title of JS lib (i.e. "QZ Tray" --> "My Printing App")

[tresf]

qz.api.getTitle(); // returns "QZ Tray"

// Change all internal JS references of "QZ Tray" to "My Printing App"
qz.api.setTitle("My Printing App");

qz.api.getTitle(); // returns "My Printing App"

- Error: Unable to establish connection with QZ Tray
                                             ^^^^^^^

+ Error: Unable to establish connection with My Printing App
                                             ^^^^^^^^^^^^^^^

- Established connection with QZ Tray on 8181
                              ^^^^^^^

+ Established connection with My Printing App on 8181
                              ^^^^^^^^^^^^^^^