Changed ChatBox.mxml to use the arrow keys to navigate chat messages.
Localized some special-case strings being used in Shortcut Window.
Improved Chat Box navigation logic and initial accessibility description.
Improved 'Repeat Current Message' functionality for repeating the Welcome message before any other navigation happens (an edge case, but an easy one to address)
Changed hotkey for Repeat Current Message to the Spacebar.
Merge pull request #190 from SenecaCDOT-BigBlueButton/chat-access-hotfix

Chat access hotfix