(maint) Remove incorrect doxygen line
(doc) Remove duplicate info and add details.

OpenSSL was mentioned twice, so the entry under Visual Studio was fixed.
Some download instructions were also clarified.
Merge pull request #88 from MikaelSmith/doc/master/update-windows-instructions

(doc) Remove duplicate info and add details.
(maint) Clean removed package references.

Some references to RE2 and LOG4CXX were missed when removing the packages.
Remove those missed references.
Merge pull request #89 from MikaelSmith/maint/master/clean-removed-lib-refs

(maint) Clean removed package references.
(CFACT-44) Add missing Facter.version method.

Adding a missing Facter.version method that returns
Facter::FACTERVERSION.
(CFACT-44) Support boolean values in confines.

Support true and false in a Ruby confine hash.
(CFACT-44) Implement exec and which on Facter::Util::Resolution.

Implementing exec and which singleton methods on
Facter::Util::Resolution.

These call directly into the corresponding methods on Facter::Core::Execution.
(foo)
(bar)