Expected behavior for status tested

This is the first round of libgit2 status tests.
Added ignored status
Merged test cases and teardown repo
Merge pull request #370 from muff1nman/status-tests

Expected behavior for status tested
bump libgit2 to a59826
bump libgit2 to 4c4408
bump libgit2 to 9331f9
bump libgit2 to 530594
bump libgit2 to 433ba6
bump libgit2 to 5d91be
bump libgit2 to 065a00
Tests: The index tests should use a valid filemode.

Filemode validation was introduced in libgit2/libgit2@052a2ffde4.
Repo: Update to new signature of git_merge_analysis.

git_merge_analysis has new preference output parameter. It's left unused
for now, but compiling rugged works again.
bump libgit2 to 19d77c
Tests: Ensure that we perform git-aware clones.

If we don’t specify the  `file://` protocol part in the path we give to
`Repository#clone_at`, we will perform a local clone, which won’t
trigger any callbacks.
bump libgit2 to 5f0527
CI: Build Rugged on OS X.
Bump the ruby 2.1.x version.
Allow the OS X build with Ruby 2.1.2 to fail.