Validate HTML

[Iain-S]

We could use libtidy to validate the html rendered by jinja for the main and detail pages?

See http://countergram.github.io/pytidylib/

[Iain-S]

At the same time, we could check that all our jinja templates are valid.

See, for inspiration, https://stackoverflow.com/questions/37939131/how-to-validate-jinja-syntax-without-variable-interpolation