(CFACT-116) Add Windows identity fact

Uses GetUserNameEx to retrieve the same information as whoami.
(CFACT-116) Add Windows timezone fact

Safe version of localtime on Windows is localtime_s, as opposed to the
POSIX localtime_r.
Merge pull request #200 from MikaelSmith/task/master/CFACT-116-Windows-id-tz-facts

(CFACT-116) Add Windows identity and timezone facts
(maint) Simplify use of Windows sys error message