Add tr() to translatable strings
Added optimised string concatenation (replaced '+' with '%')
Made accessor methods const; made serverName parameter const in QWebSocket
Removed virtual from open and close methods
Removed default values from methods in private class
Disconnect previously connected signal (was forgotten)
Adapted documentation to qDoc style
Replace QT_BUILD_SERIALPORT_LIB with QT_BUILD_WEBSOCKETS_LIB