Handle exception when sending message to client

 Handle exceptions properly when sending message to client. We were not handling the
 exception so when it occured, the thread stopped and we can't send messages from
 server to client anymore.

Fixed userlist and chat scrolling in Firefox

bbb-conf now recommends editing external.xml if FreeSWITCH is listening to 5066 with SSL enabled 

bbb-conf --check warns you if you have SSL configured by still have FreeSWITCH listening on port 5066

Cleanup formatting of port for nginx in bbb-conf --check

Escaping Java's properties file instructions

In recording playback, chat links open in a new tab

Fixes #3590

html5client: limit sound on unread chat via Settings and Config

recover redirect to html5 client on android device

Fix typo in closed caption locale string

add German to html5 client (from Transifex)

HTML5 - clear status on userlist

Remove screenshare WebRTC options from config.xml

Fix screenshare preview on reconnect. Fixes #3252

HTML5 - arrow key of presentation

HTML5 Client sound - added sound for unreadMessages -Tested, works fine

Filter out webcam duplicates. Also fixes #3572

Add custom poll option text to locales