js/ui/environment.js: Split out initial UI setup (Tweener initialization,
Nbtk monkey-patching) into a separate file we can import from tests.
tests/: Directory for various types of tests
tests/run-test.sh: Shell script that to run tests with an appropriate
environment set up.
tests/testcommon/: Common modules and data for tests
tests/interactive/: Interactive tests
tests/interactive/box-layout.js: A sample test of NbtkLayout
