This commit is related to #231, #243, #256, #233

Cloud-Service
- GoogleCloudService deals with all google-api related functions
- If file archive button is pressed, GoogleCloudService tries to upload the file.
- If file-upload(archive) succeeds, (filename)-archive.json file and google fusion-table entry are made
- If file-upload(archive) fails, the service will try to upload next time when the application starts again.
 (The application will pop up a dialog for google-account right after the application starts if the upload failed before)
- The file-upload(archive) procedure continues, even though a user closes the application
- Archive File Format
(filename)-archive.json: name, groupID, upload-success date
Fusion Table entry: Identifier(filename), name, file_type, language, speakers, upload_approved_date, upload_success_date, [data_store_url, tags, discourse_type are currently dummy values]