Update to upstream libgit2
Merge pull request #180 from rowanj/update-libgit2

Update to upstream libgit2
removed -remoteBranches

use -trackingBranchWithError:success:
Merge pull request #182 from libgit2/remove-remote-branches

Removed -remoteBranches
Include SHA in GTCommit.description
Merge pull request #184 from libgit2/better-commit-description

Include SHA in GTCommit.description
use int as the underlying type for libgit2 enums
updates for Xdacted
Revert "updates for Xdacted"

This reverts commit 33ee2d76f488874284aa5f375bbff549502937b4.
updated for Xdacted again, but without the auto architecture stuff
++specta + expecta
immutable some things
don't specify the underlying type
Merge pull request #185 from libgit2/fix-underlying-types

Use int as the underlying type for libgit2 enums
first pass at some obvious thread safety problems
more thead safety fixes
import OSAtomic
Bump to get libgit2/libgit2#1651
-force_load all libgit2 symbols so they're available to consumers
Use -all_load instead of -force_load on iOS #LibtoolLulz