Location of JS/script assets in the HTML

[mortenpi]

The user can include additional JS scripts in the HTML page by passing the URLs via the assets keyword to HTML. Currently, the generated <script> tags get placed after the built-in dependencies (including RequireJS, which can cause issues). Based on that discussion, it looks like we could handle it better:

• [ ] By default, place the user-provided <script> tags before the RequireJS loading (works around the issues with libraries that do not play well with RequireJS if they are loaded separately: https://github.com/requirejs/requirejs/issues/947#issuecomment-28677913).
• [ ] Allow the user to customize the location with a keyword to asset() (e.g. before, after RequireJS, at the end of the HTML file).

[baptiste]

Have you seen workarounds for three.js? I'm hoping to use it for 3D visuals in my docs, but unless I manually move the <script> above requirejs it doesn't seem to work. (strangely it kind of works if I use an old version of three.js, but there are too many features missing – here's a self-contained example that I can't integrated in docs)

[ericphanson]

This would be useful for https://github.com/asciinema/asciinema-player too, to include asciinema gifs. Re- https://github.com/asciinema/asciinema-player/issues/142