Updated cRDPEnabled

Added NLARequired, which sets Network Level Authentication for RDP.
Added EnableDefaultFirewallRule, to enable the default remote desktop
rules in Windows Firewall. If set to false, it will ignore the firewall
settings, to allow for another source to control firewall rules.
Tweaked some code.
Merge pull request #62 from llstrk/cRDPEnabled-change

Updated cRDPEnabled