Fix inaccurate documentation
Remove reference to withCheckout.
List acceptable parameters for the options dictionary
Limit comment lines to 80 chars

Excluding spaces.
Line up with comment body. Not comment start.
Wrap GTRepositoryCloneOptionsBare to the next line.
Actually make the comment line up.
Merge pull request #268 from PiersonBro/fix-inaccurate-documentation

Fix inaccurate documentation