GUACAMOLE-118: Use poll() when waiting for data to be written to the terminal emulator.
GUACAMOLE-118: Use poll() when waiting for data to be written to the terminal emulator.

apache/guacamole-server,glyptodon/guacamole-server,apache/guacamole-server,mike-jumper/incubator-guacamole-server,mike-jumper/incubator-guacamole-server,apache/guacamole-server,glyptodon/guacamole-server,mike-jumper/incubator-guacamole-server,mike-jumper/incubator-guacamole-server,glyptodon/guacamole-server