Barrier support

[bernharl]

This works with Synergy-Core, does it also work with the Barrier fork?

[quoing]

You need to do some minor changes, like update hello packet to accept barrier hello. I didn't try to use this so there might be more changes required ;)

https://github.com/symless/synergy-micro-client/blob/master/uSynergy.c#L214