Annotation Tools: Added Grouping Plug-In

**Background: ** During our last course launch we noticed that if hundreds of people are annotating a text, it all very quickly overlaps and the text becomes chaotic and unreadable. This update adds a "Grouping" button that can be toggled on or off that would group annotations based on line position.

**Studio Updates: ** None.

**LMS Updates: ** Only in text annotations you should see a new button pop up that shows whether grouping is turned on or off. Add any number of annotations and those that **begin** on the same line will get added to the group. Clicking on that group will show only the annotations that are contained with in that group. 

**Testing:** Add the text annotation tool via "advanced modules" in Advanced Settings for the course. Then make sure annotation_storage_url and annotation_secret_token are set. Head over to a unit and add the component. whenever you add annotations, if the button says that the grouping is on then the highlighting will not show up, but rather a sidebutton with the number "1" or whatever number of annotations you've added. Default for Public is grouping turned on and default for everything else is grouping turned off. 
spacing after commas (thoughout PR)