Added audio alert; when Presentership is moved to or from a screen-reader user, that user is notified of their status change.
user list alpha sorting is now ascending instead of descending
Merge pull request #160 from SenecaCDOT-BigBlueButton/fix-sorting

user list alpha sorting is now ascending instead of descending
Merge branch 'access-presenter-alert' into stable-access-test
 - stop sending video streams to red5 when the user logsout
Added separation between global hotkeys and local-to-module hotkeys. Also changed hotkey modifiers to more favourable combinations.
Improved the global/local logic by eliminating loadGlobalKeys() and merging the functionality into loadKeys(). Also made a shortcut function string more clear.
Merge branch 'better-hotkey-modifiers' into stable-access-test