DriveGraph.java: found a way to monitor changes on remote Google drive server.
DriveNode.java: Someone mention that Google Drive's Java client API doesn't implement resumable upload. However after tracing Google's code I found that it seems to be already using the resumable upload proposed in https://developers.google.com/drive/manage-uploads#start-resumable. Please check my answer on StackOverflow: http://stackoverflow.com/questions/19360990/setting-uploadtype-in-google-drive-java-api/20918045#20918045