add function to init repos w/custom odb backends
Stop assuming ODB backend includes wrapping routine; wrap in git2go instead
Refactor InitRepositoryWCustomOdbBackend() into component functions
Rename constructor functions to New...
Add OdbBackend constructor
remove unnecessary comment
Merge branch 'master' into custom_odb
Merge branch 'catchupTo66af84' into custom_odb

Conflicts:
	git.go
	reference.go
	repository.go
	submodule.go
add OdbBackend.Free() and the C it wraps; go fmt odb.go
add custom refdb backend support
Merge branch 'master' into custom_odb

Conflicts:
	git.go
	reference.go
	repository.go
	submodule.go
re-encapsulate repository
explicit returns
Merge branch 'master' into custom_odb

Conflicts:
	odb.go
	wrapper.c
update for upstream changes
fix for travisci
Merge commit 'refs/pull/48/head' of github.com:libgit2/git2go