Changed check for undefined autoRestart option
Removed extra line break.
Added support for two new events to attach callbacks to: errorNetwork and errorNotAllowed. (#61)
If permission isn't granted, don't autorestart
Replaced callback errorNotAllowed with errorPermissionDenied (when a user actively denies the permission request) and errorPermissionBlocked (when the browser automatically denies the permission request). #61
Tweaked check for permission deny type so it's slightly tighter
Added many comments
addCallback() now receives an optional third parameter with the context to run the callback function in