Multiple Users Annotating Recordings

[BryonLewis]

resolves #25

This PR is intended to allow other users on the system to annotated and make annotations on other's recordings.
To do this there is now an option when uploading (and can also be edited) called public. This allows others to see the recording and create annotations on it.

Done:

• Added the public field and created a migration for it in the recordings
• Updated the POST and added a PATCH to set Public state on Recordings
• The Main Recording view now has your own annotations plus annotations that are shared with you.
• You can see the number of distinct users that have made annotations on your own recordings.
• You can also see if you made annotations on a shared recording.
• When returning spectrogram data back with annotations it will also include the list of users who have made annotations on your recording
• Included a currentUser response for the specotrgram, this is used for styling of annotations in the list
• Updated the LayerManager and layers to have otherUserAnnotations which is a dictionary of annotations by other users which can be added to the current view.
• Other User Annotations only show up on your own recordings, you can't see other's annotations for their recordings.
• Imported D3 to create an ordinal color system for the usernames, but eliminates the red/yellow/cyan for the default colors.
• Prevent editing of other user's annotations (you can't even select them)

BatsSharing.mp4