Updated various UI elements

ConnectionList: added green padlock to encrypted connections,
changed connections that use cert auth to display cert alias
instead of connection username, added auth type in connection
subheader, updated layout refresh to prevent recreating activity,
added protected intent broadcast receiver to allow for layout
refresh when background service errors out.
ConnectionDetails: updated UI to disable "Username" field when
cert auth is used, and to allow field to be blank in that case.
AppRTCClient: updated to prevent displaying error message when
connection is intentionally stopped by the user.
SessionService: updated to send protected intent broadcast upon
erroring out.