xfreerdp method: use new command line interface

[hador]

Use the new command line interface instead of the old, deprecated one for xfreerdp.
For more information refer to FreeRDP#CommandLineInterface.

[bogbert]

Hi hador,
your changes contain a small bug regarding the sound option.
The problem is line 257 of lib/method/PACMethod_xfreerdp.pm
It should be:
$txt .= ' **/sound:sys:alsa' if $$hash{redirSound};
instead of
$txt .= '+**sound:sys:alsa' if $$hash{redirSound};

[hador]

fixed, thanks!

[figue]

Why this merge isn't done yet? Is there any particular reason to keep using and old version of freerdp?