[#108] "Error: Unencrypted communication not supported" with 0.8.0 and winrm #108

@adamedx  @muktaa 
It includes:
1> I've added changes to fix https://github.com/opscode/knife-windows/issues/108 issue.
2> @siddheshwar-more has fixed bug related to winrm session exit code

What about when the user is given as ".\testuser" ? Can we get a test for that?