Insert progress elements using insertHTML.
Make all extra element for uploading not selectable.

Fix wordpress-mobile/WordPress-iOS-Editor#394
Fix wordpress-mobile/WordPress-iOS-Editor#301
Fix wordpress-mobile/WordPress-iOS-Editor#132
Reduze timing upload
Add missing container id code.
Explicit declare and explain hiddenChar.
Code reorganisation.
Refactor code for adding container, progress, and hidden char.
Remove timer from dictionary when finished.
Merge branch 'release/0.3' into feature/improve_media_progress
Merge pull request #435 from wordpress-mobile/feature/improve_media_progress

Feature/improve media progress