Removed unused import
added isEmpty() method
Only prompt to confirm clear message action if there are messages
Sheet accessed by ID's instead of names, files now movable in drive.
Ensure messager number is url encodable
Removed sheet name from message upload URL, as sheet ID now stored by
script
Merge branch 'master' into dev
Publish as v1.2 / build 5
Removed redundant warning about renaming/moving TATupload drive
documents
Updated tutorial text
Updated to build 6, v1.2.1
Fixed opening ParameterViewActivity from settings