Replace vendored theme with commonjs import and bower sources

[agjohnson]

This stops using manually vendorized theme bits in several places:

• Vendorized theme templates
• Theme javascript copypasta
• Manually imported CSS files for the theme
• Manually imported font files

This complete drops the vendorized theme 🔥

I don't know what purpose it served in the past, but it seems unnecessary when
we're installing the theme in each virtualnev anyways. I could have missed
something here. This leaves the layout.html override, but removes the other
files which all looked unused or unwarranted.

Theme javascript copypasta is replaced with a CJS import from a bower-installed
sphinx-rtd-theme package. The manually imported CSS and font files from the theme are
also installed from bower sources now. Unnecessary links for font files were dropped based on hit in our server logs.

Bower/pip are temporarily pointing at a branch on the theme repo, this will be
changed to a release or release tag after.

Blocked by readthedocs/sphinx_rtd_theme#243
Fixes #1501

[gregmuellegger]

Local test was successful. Pop-out works, theme is cool. No 404 requests from the docs page.
I only don't understand what you are doing with the fonts, however it seems to work :)

Everything else looks good to me.

[agjohnson]

This just moves the theme font/css bundling to bower + gulp along with newer assets. It doesn't necessarily need to be from bower sources, but it at least seems a little more predictable, or at least explicit.

[f0k]

I think this broke the build for us: https://readthedocs.org/projects/lasagne/builds/
Before this PR it worked, now it says "ThemeError: no theme named 'sphinx_rtd_theme' found (missing theme.conf?)"
The relevant section in our conf.py is as follows:

if os.environ.get('READTHEDOCS') != 'True':
    try:
        import sphinx_rtd_theme
    except ImportError:
        pass  # assume we have sphinx >= 1.3
    else:
        html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
html_theme = 'sphinx_rtd_theme'

That is, if running outside of readthedocs and with an old version of Sphinx, it imports sphinx_rtd_theme and sets html_theme_path. Then it sets html_theme, no matter if running on readthedocs or not. This worked fine, now it doesn't.

Note that we have Sphinx==1.2.3 in our requirements.txt because of sphinx-doc/sphinx#1822 (which will only be fixed in Sphinx 1.4). We then relied on readthedocs setting the theme path for us.

Why has this been removed, and how can we work around it? (I assume if we just remove the os.environ.get('READTHEDOCS') check, we'd fall back to using the PyPI version of sphinx-rtd-theme. But I'd rather like to hear your suggestion than committing a couple of different things to try!)

Thank you!

[agjohnson]

If this is still an issue, open a ticket, it will have more visibility. I believe we deployed a fix for this yesterday.

[f0k]

Thanks for getting back to me! I was aware that this was not the most obvious place to report problems, but figured you'd be notified and you'd know best. The build works again if we intend the html_theme = line so the variable is not set when running on readthedocs. Cheers!