Atto media plugin: add title global attribute support

Setup Ensure you have a small video (mp4) and audio clip (you can use the same clip) Create a course with a forum in it Navigate to this forum and add a new post Note: The following tests follow on from one another Video Video: Regression test Open HTML editor Click on "Insert Media" button Select "Video" tab Upload your video clip Click "Insert Media" button Click the "Show more buttons" link in the Atto toolbar (first icon) Click </> button to view the HTML source Observe that "title" attribute is not present in <video> tag. Toggle the "HTML source" button again to return to the normal editor Video: Edit existing video Select the player in the editor and click "Insert Media" button again Observe the "Video" tab is selected and source URL present Click on "Display options" sub-menu Confirm that the Title is empty Set a title Click "Insert Media" button Click </> button to view the HTML source Observe that "title" attribute   in <video> tag is now set to the value you specified Toggle the "HTML source" button again to return to the normal editor Video: Edit existing video with title Select the player in the editor and click "Insert Media" button again Observe the "Video" tab is selected and source URL present Click on "Display options" sub-menu Confirm that the Title is set to the value you set in the previous test Change the title Click "Insert Media" button Click </> button to view the HTML source Observe that "title" attribute   in <video> tag is now set to the updated value Toggle the "HTML source" button again to return to the normal editor Video: Remove title from existing value Select the player in the editor and click "Insert Media" button again Observe the "Video" tab is selected and source URL present Click on "Display options" sub-menu Confirm that the Title is set to the value you set in the previous test Unset the value Click "Insert Media" button Click </> button to view the HTML source Observe that "title" attribute in <video> tag   is not present Toggle the "HTML source" button again to return to the normal editor Video: Rendered content Add a second video: Set the title to something you will remember Note: You will now have two videos on the page - the first from the previous test without any title, and this second one with a title Post the forum post View the forum post Inspect each of the two videos: Confirm that the video without a title has a default title of the filename i.e. If your video file was called 'bananas.mp4', this name will be tht title Confirm that the second video (with a title) has the title you specified Testing audio title Repeat steps for video title testing, but choose "Audio" tab in "Insert Media" interface. You can use the same mp4 video source for audio