Localise schedule times

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

Hide unpublished talks from schedule

Use the unpublish flag on presentations to hide them from the schedule
grid/mobile view as well as the schedule lists.
Show unpublished indicator for staff.

Fix schedule edit

Use main base template instead of intermediate base.
Remove references to Bootstrap 3 and update to Bootstrap 4.
Add edit button to standard grid/mobile view instead of duplicating.

Styling for schedule

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

Show chair for session on main overview page

Plus keep it a link so opt out is not impossible.

Remove the personalised bits of session chair display

- The schedule grid page is ridculously database-query heavy and hence
terribly lacking in perfmantitude.
- Caching can help with this, but the caching implemention at present
is not user-aware. If one user looks at the page, they'll get a
"YOU" in all the places they're chair and something else everywhere
else - and then everyone will see that for the next 600 seconds,
then YOU will become someone else
- to avoid this, remove the request.user-specific bit of the template

Make narrow-screen schedule details more distinct

In the narrow view, lots of details that aren't in the normal view
appear to compensate for not having clear row/column headers any more.

However, all the detail can look very same-same; this tweak makes rooms and end times more distinct.

Session chair info is made always italic, and a label is added to make
it clear that this person is not the speaker.

Chrisjrn/session chair (#94)

* Adds session_detail page

* Adds session chairing information to the schedule grid

* Adds session_list.html

* Nicer volunteer text

Conflicts:
pinaxcon/templates/symposion/schedule/_grid.html

Conflict and migration performed by Sachi King <nakato@nakato.io>
Emoji changed, lca2017_tags to lca2018_tags, remove needless dependency
on django-user-account, use request instead like the remainder of the
calls n the template do anyways.

Remove blocktrans from a number of texts as they break {{ templating }}
and we don't translate anyways.

Modified-by: Sachi King <nakato@nakato.io>

Display Room for everything that's not break

Talks, tutorials, plenaries, miniconfs - everythign except breaks please.

If there are no track names for today, don't show the row

If there are track names today, show the row for track names. If there aren't, don't show an empty row.

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.

Rooms have optional track names, access schedule by day via URL (#87)

* Optional track name with room name on schedule, access schedule by day eg /schedule/?day=Monday

* Changed to using a Track model rather than a char field

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.

Schedule tweaks etc (#80)

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