Merge pull request #2 from Gagravarr/master

Set up a git ignore file
Allow fetching of a DriveFile object by NodeRef

To avoid users of the GoogleDocsService having to know too much about
the underlying Alfresco datamodel being used, provide a method to
fetch the DriveFile object by NodeRef, and update existing code to
use that.

Closes Alfresco/google-docs#3