Separated thumbs snippets (HTML/JS/CSS) into separate files,
which are loaded using pkg_resources.
Added Jasmine test for thumbs.js.  This commit does not include
the Jasmine or JQuery libraries, which are required for the
tests run.

Also modified thumbs.js to make it easier to mock out JQuery.

Set up Jasmine tests to use Jasmine gem (Ruby) as test runner.

Added README explaining the JavaScript tests

Added README describing directory structure.

Modified main README to mention JavaScript unit tests