xsetwacom call fix using regex

in module xsetwacomadaptor.cpp, functions getParameter and setParameter, there is an invalid call to xsetwacom command. the param variable should be splitted by whitespace so it is not regarded as one argument. (the other parameters (device and value) should not be splitted - see xsetwacom manual page) The current fix is not accurate enough : it solves the problem only for the 'Button' case and not for other cases like 'Area x1 y1 x2 y2'. Without the new fix, the xsetwacom command will fail, and the tablet configuration won't work.