Update to libgit 0.21.4#336

Merged

johnhaley81 merged 4 commits intomasterfrom

Jan 20, 2015

Commits on Jan 19, 2015

Updated to libgit 0.21.3
John Haley
committed
Added new files for the windows build
John Haley
committed
Bumped to libgit2 v0.21.4
John Haley
committed
Added 0.21.4.json file so nodegit builds again
John Haley
committed