When the render function is run now, it uses the partial_finder
function to search recursively through files for partials and add them
so that test writers don’t have to.
This means that we no longer have to do any manual work to maintain
the templates.js check that all handlebars templates are rendered by
the node tests.
This makes sure we are explicit about partials in
individual test modules. Eventually, we should figure
out a way to make partials automatically compile as
part of the node tests.
This introduces a very minor different in behavior if you specify
an invalid filename as a command line argument. We now show
warnings for those *before* running the rest of the tests.