Smartcard in ThinLinc environment

Detect if we're are into a ThinLinc session runs from a windows client.
Tested successfully in those environments : 
1/ Linux Ubuntu (xfreerdp) => Remote Windows Machine
2/ Linux Ubuntu => Thinlinc Server (xfreerdp) => Remote Windows Machine
3/ Windows Machine => ThinLinc Server (xfreerdp) => Remote Windows Machine

I noticed that removing the line #1476 (states[j].dwEventState &= 0xFFFF;) in winpr/libwinpr/smartcard/smartcard_pcsc.c also worked for the 3 environments above (at least with my reader & middleware) but
as maybe this masking could be important for others I prefer detect If we're in a thinlinc environment runs from a Windows client.

I'm not in favor of having thin client specific code upstream.