Merge pull request #2 from elehcim/master

Fix oid test and a typo
Update .travis.yml
update .travis.yml, speedup build by only downloading repo tip
cleanup deprecation warnings for index
cleanup deprecation warnings for blob
cleanup deprecation warnings for diff
cleanup deprecation warnings for object
cleanup deprecation warnings for repository
fix tag / signature test
Merge branch 'master' of git://github.com/jakebolewski/LibGit2.jl
fix remote test
attempt at fixing travis threading error