Switch templating engine to Handlebars on the client.

Update the Renderer.

Resolves #351

Update Renderer with Handlebars changes.
Update comments.
Upgrade to Marionette v2.3-pre.
v0.1.20
support postinstall.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Change port to 3344; add warning about changing it.

Resolves #358
Add back toJSON shim. Add more shim comments.

Resolves #360
Remove unused reference to titleView.

Resolves #357
Place dropdown menu over loading overlay.

Resolves #353