build(browserstack): initial setup

Closes #4941

scripts/ci/test_browserstack.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -e
+
+echo =============================================================================
+# go to project dir
+SCRIPT_DIR=$(dirname $0)
+cd $SCRIPT_DIR/../..
+
+./scripts/browserstack/start_tunnel.sh
+./scripts/browserstack/waitfor_tunnel.sh
+./node_modules/.bin/gulp build.js.dev
+./node_modules/.bin/gulp test.unit.js.browserstack/ci