Added additional remote methods

Added the following methods:

- git_remote_create
- git_remote_rename
- git_remote_name
- git_remote_pushurl (untested, has been segfaulting)
- git_remote_delete
Merge pull request #206 from nodegit/more_remote_methods

Added additional remote methods
Added new methods in checkout and repository
Merge pull request #207 from nodegit/checkout-methods

Added new methods in checkout and repository
Fixes EJS not being installed via NPM