Localise schedule times

Show local times on schedule and presentation details
if user is in a different timezone to the conference.

Update to Django 2.2

Upgrade site and modules to Django 2.2. Remove and replace obsolete
functionality with current equivalents. Update requirements to latest
versions where possible. Remove unused dependencies.

Fix presentation detail

Do not retrieve schedule if it does not exist for proposal kind section.
Do not show slot information if slot is not assigned.

Improve schedule - speaker nav

Add link to speaker profile from presentation detail page.
Include twitter and homepage on speaker profile.

Update speaker styling

Use site base template for all pages.
Fix speaker profile to work with Bootstrap 4.

Styling for schedule

Update to Bootstrap 4 throughout.
Remove unused blocks and elements from past conferences.
Ensure schedule works in print mode.

Switch to LCA2020

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

urlize abstracts

I've looked through the database and I can't find any accepted
proposals that actually contain anything to linkify - but I've had
several requests from people that I think are reasonable, things like
being able to link to their project (we ask them to provide a project
url but we don't use that link)

This seems like a reasonably fast way to let those people add a
link. We still have to manually accept changes to their proposal so we
have a chance to look at the content of the url if we want.

The urlize filter adds rel=nofollow to the link automatically.

Improve display of abstract and presenter bio

Relocate buttons to be beside the presenter's name.

Format abstract and bio in monospace hack as intended.

The 2018ificiation

I think this removes most references to "hobart", "pycon", and "2017"

There are still some references to some images that we don't have a
replacement for.

move templates out of vendor specific locations

Lets not kid ourselves. The whole apps templates are client specific.
Lets just remove that and not think it isn't.

Switch to LCA2017 templates

This fixes proposal details.

Adds mobile-friendly schedule view and paged schedule view (#81)

* Adds responsive mobile CSS for schedule timetable

* Adds by-day schedule view

* Displays content_override in schedule

* Adds twitter/homepage links for speakers.

September website changes - Pre-registration (#66)

* Factors rendering of external links into its own template. Automagical!

* Adds wagtail templates for keynotes on the front page

* Migrates to Wagtail 1.6

* Migrates content pages to be a streamfield. Flexibility++.

* Fixes editing of ContentPage bodies

* Adds floating images to content pages

* Fixes the layout of floating images

* Adds anchor links to content pages.

* Adds presentation link to the keynote speaker block model

* LCA-ifies the schedule list

* Refactors cms_pages/content_page into a new base template

* cms_pages/content_page now derives from abstract_content_page

* news_index_page now derives from abstract_content_page

* news_page now derives from abstract_content_page.html

* utility_page now uses the content_page base template

* Factors out _right_floating_image.html

* Themes the presentation detail page

* Themes the speaker profile page.

* Themes the schedule list page.

* Minor work on schedule_conference.html

* Themes schedule_detail.html

* Replaces cradle.svg

* Adds a background image to the schedule pages

* Adds libravatar fallback for speaker profile images

* Adds new background images (must update colophon)

* Adds some magic so that we can have slightly different presentation backgrounds for different pages.

* Adds the sponsor block to the bottom of the page.

* Adds sponsor logos to footer.

* All migrations are now in this tree

* Fixes wagtail migrations

* Adjusts presentation_detail to allow for miniconfs (i.e. no target audience)

* Adds unpublishing to presentation detail

* Adds ScheduleHeaderParagraph, which allows us to add some text to the header of schedule pages.

* Adds NamedHeaderParagraph. It allows us to store header paragraphs in the CMS.

* Date formatting in the schedule

* First step for fixing images

* Allows us to automagically load the colophon

* Adds “publish changes” button.

* Can login with email address

Minimum viable changes to get schedule to display (#64)