Add websocket stresstests for Tornado server

.gitignore

@@ -168,3 +168,4 @@ darwin.interactive.json
 junit.xml
 python/perspective/python_junit.xml
 python/perspective/coverage.xml
+python/perspective/bench/stresstest/results

package.json

@@ -108,6 +108,7 @@
         "build_python": "node scripts/build_python.js",
         "bench": "node scripts/bench.js",
         "bench_python": "python3 python/perspective/bench/perspective_benchmark.py",
+        "stresstest_python": "python3 python/perspective/bench/stresstest/main.py",
         "_wheel_python": "node scripts/_wheel_python.js",
         "setup": "node scripts/setup.js",
         "docs": "node scripts/docs.js",

python/perspective/bench/stresstest/__init__.py

@@ -0,0 +1,7 @@
+################################################################################
+#
+# Copyright (c) 2019, the Perspective Authors.
+#
+# This file is part of the Perspective library, distributed under the terms of
+# the Apache License 2.0.  The full license can be found in the LICENSE file.
+#

python/perspective/bench/stresstest/client/__init__.py

@@ -0,0 +1,7 @@
+################################################################################
+#
+# Copyright (c) 2019, the Perspective Authors.
+#
+# This file is part of the Perspective library, distributed under the terms of
+# the Apache License 2.0.  The full license can be found in the LICENSE file.
+#