For CI - workaround intermittent network I/O error on Travis-CI.

script/dockerized.sh

@@ -28,6 +28,9 @@ PROJECT_DIR=$(cd ${0%/*}/..; pwd)
 BuildEnvironment=-$1; shift
 BuildEnvironment=${BuildEnvironment/-base}
 
+# Workaround Travis-CI intermittent network I/O error
+if [[ $TRAVIS ]]; then while (! docker pull urho3d/dockerized$BuildEnvironment); do sleep 10; done; fi
+
 if [[ $(docker version -f {{.Client.Version}}) =~ ^([0-9]+)\.0*([0-9]+)\. ]] && (( ${BASH_REMATCH[1]} * 100 + ${BASH_REMATCH[2]} >= 1809 )); then
     docker run -it --rm -h fishtank \
         -e HOST_UID=$(id -u) -e HOST_GID=$(id -g) -e PROJECT_DIR=$PROJECT_DIR \