Will render if a file exists at: static/local/custom.css

Ref T563

Ref T770

The header shouldn't include the `dated` property, since we don't display a date
on pinned posts. This fixes that.

This supports a new `monetization_pointer` collection attribute.
When present, we include the `monetization` meta tag on all
collection pages.

Ref T669

Previously, the date format in this attribute for posts was invalid.
This caused local date rendering to fail in Firefox. This fixes that.

Closes #253

Dates now display on blog post pages if the collection's chosen display
format is "Blog". It updates the chorus-collection-post template to now
respect this value (previously, it always showed the date).

Ref T669

This changes all variables and functions from using Suspend{ed} to using
Silence{d} as well as documentation, errors and logging.

This fixes a template rendering issue caused by bad references to $.Host
in pinned posts links on single-user instances.

Closes #207

the change to take a hostname in Post.CanonicalURL broke a few template
using that function. This adds a Hostname string to the Post being
passed to templates and passes it to calls to Post.CanonicalURL

- update error messages to be correct
- move suspended message into template and include for other pages
- check suspended status on all relevant pages and show message if
logged in user is suspended.
- fix possible nil pointer error
- remove changes to db schema files
- add version comment to migration
- add UserStatus type with UserActive and UserSuspended
- change database table to use status column instead of suspended
- update toggle suspended handler to be toggle status in prep for
possible future inclusion of further user statuses

this adds a helper script to rewrite all time elements with a proper
datetime attribute into the users locale via the browser
navigator.language.

collection, collection-post and chorus-collection-post templates now
include this script

This displays the "page is missing" text within the same page as any
other blog post, keeping customizations, pinned pages, and general blog
navigation.

Ref T493

This closes #1

Might as well do this right away, we're here anyway.

It now loads unconditionally and highlights all code blocks.

TODO: optimize to not load when there are no blocks

This is a first stab at having a configurable code highlighting option,
similar to the MathJax rendering option. This change makes a checkbox
in the settings for code highlighting using the highlightjs.org
library.
What works: code highlighting in multi-user env is like I would
expect. single and anon(?) needs work

Things to resolve/consider:
- does the .IsCode test for code highlighting need to stay? At least
this and that should use the same version of the highlight.js lib.
- can the common templating part be 'included' somehow?
- the anon vs single-user vs multi-user code is not completely
clear (to me)
- bring js to local instead of cloudfare cdn (perhaps combine with
MathJax)

- New editor nav
- New backend nav
- Support for drafts
- Different footers on backend