Newer versions of the win32 gems depend on ffi when running under ruby 1.9.

This commit mentions to the user (during installation) that puppet has a
dependency on ffi, which is licensed LGPLv3.

Since the puppet installer is a "Combined Work" containing Artistic 2.0,
ASL 2.0, MIT, and LGPLv3, we "Accompany the Combined Work with a copy of
the GNU GPL and this [LGPLv3] document"[1] to the license file displayed
to the user in the Installer dialog.

[1] http://www.gnu.org/licenses/lgpl.txt
Maint: Add LICENSE to the project

Add a license to the project
Maint: Update Gemfile

Previously, we were using a deprecated gem source. Also there's no need to
check in the Gemfile.lock, updated the .gitignore accordingly.
Merge pull request #48 from joshcooper/ticket/master/21286-ffi-dependency

(#21285) Add ffi dependency to license