Switch to LCA2020

Remove LCA2018 and LCA2019 styles and content.
Add base LCA2020 styling and update references to year.

Improved menu styling

Update menu to use same style as static site,
with slight adjustments for Bootstrap 3.

Enable multi-level site-tree

* Remove the outdated compiled javascript once again
* Update the sitetree_header template to use more detail.

The extra detail here is taken from the menu_bootstrap3.html template
distributed with django-sitetree

Bootstrapification: SiteTree Nav Bar

Make sitetree a bootstrap navbar.

Remove mobile menu, bootstrap provides this.

Default content page and sponsor list is working, mostly.
TODO: get sponsor logos to show up instead of the names (text).

Fixes for 20160718 (#54)

* Simple form input fields now use TakeFlight styling

* Styles the form widgets as per the styles in our CSS

* Styling of TextArea now matches the remaining input types

* Adds is_last modifier to navigation dropdown

* Adds admin for talk, tutorial, and miniconf proposals

* Adds an RSS feed

* Adds a link to the RSS page

* Unbreaks the old news index page

* Adds never_cache to the login page, removes the never cache middleware from the settings

Thursday + Takeflight changes (#31)

* Adds Facebook svg button, and adds Facebook link type to models

* CSS work from takeflight, 30 June 2016

* Adds drop-down menus for navigation

* Adds mobile menus for navigation

* Minor tweak to mobile nav headings

* Makes the logo a link back to the homepage

* Updates the footer to the current version, removing sponsor logos for the moment.

Templates (finished?) (#22)

* Adds inset_illustration as a drop-down of svg data rather than as an uploady thing.

* Adds external link types to the homepage models

* Migrations

* Initial site template with our new shiny templates

* Moves all lca2017-specific assets to lca2017 subdirectory; symlinks from dist

* Reflects changes in site_base

* Deletes most of new assets in dist/

* WIP home page

* Adds external link list support

* Adds white-right panel type to the home page

* Removes an oops

* Adds copyright text to the site.

* Updates the remaining illustrations to be more compact.

* Adds illustration field to content_page, and adds fields into the news page.

* News index page

* News page is done!

* Formats the dates properly

* Commits migrations

* Optimises SVG files

* better logo

* oops

* Removes margin on logo.

* Optimises svgs, and uses tania’s originals

* One more