(FACT-186) Express windows specific gem dependencies

This supersedes and closes #591.

Previously, if a ruby module on windows tried to use facter as a
library, the calling module had to know about facter's platform specific
dependencies. This comes up when trying to develop and test puppet
modules on windows.

This commit adds the windows specific gems (which mirror the Gemfile) to
project_data.yaml. The build pipeline will automatically create an
x86-mingw32 gem in addition to the generic one.

This also loosens the Win32 platform gems and CFPropertyList to allow the
third version number (patch)  to be determined at install time. This allows better 
compatibility as we make future updates to dependency versions.