Added comments for better code review and understanding;
Fixed time string conversion error;
Fixed sendMetada dead loop (due to user deletion of google drive directory) which leads to file uploading failure;
Fixed sendFile failure (due to user deletion of google drive directory) which leads to current directory cannot be uploaded(1 hour's video files may not be uploaded at most);
Other trivial code modification.
Replace GDriveUploader and reboot to test the new script (Some exceptions may not be covered).
New script can be tested on the camera or a local Linux machine.