Ignore .ds_store
Support for tag and branch contains “”/
Add commit summary method

Sometimes, commit messages are longer than one line. The new
Summary() method returns just the first line of the commit.
Merge pull request #1 from clee/master

Add commit summary method
Remove superflous defer
Merge pull request #2 from kjk/master

Remove superflous defer
add write blob
add create branch
add create tag
remove old file
update api and merge