Allow noscript fallback to be disabled

[benbalter]

Fixes #17.
Fixes #26.

[parkr]

@benbalter Great! Just needs a test. Thank you!

[benbalter]

Great! Just needs a test

Done (with docs too!)

[parkr]

LGTM. Once CI gives the 💚, we can merge.

[parkr]

@benbalter To fix CI, gist must be defined in your block like output.

let(:gist) { "mattr-/24081a1d93d2898ecf0f" } # choose a different ID if you want :)