It seems that rsync triggers these events, so we must handle these in
addition to the IN_CLOSE_WRITE ones triggered by re-saves.

Also fix MakeDir() to correctly make parent directories (i.e. mkdir -p).

Previously we had a template tag limit of 16. This commit lifts that
limit to support "unlimited" tags per template.

Skip already offset landmarks most efficiently when adding a new asset.

New template tags:
    __CINERA_SEARCH_URL__
    __CINERA_VOD_PLATFORM__

Database version 4

Revving resources involves hashing asset files and appending a query
string to their URLs. Additionally we monitor asset files for changes
and edit their new checksum hash into all HTML files citing them.

This commit also introduces new template tags for assets (listed below)
with which you may instruct Cinera to rev assets of your choice. There
is further information about this in the help (-h) and the README.md

Amongst other minor changes, we now support unset $XDG_CACHE_HOME and
$HOME
    - Thanks to insofaras for wordexp()

New flags:
    -Q Set query string

New template tags:
    __CINERA_ASSET__
    __CINERA_CSS__
    __CINERA_IMAGE__
    __CINERA_JS__

Renamed template tag:
    __CINERA_SEARCH__ (was __CINERA_INDEX__)

This allows search result links to open in the same tab, and prevents
automatic scrolling to the search input box on page load

Previously it could fail to generate an index if the processing of the
final file set "Inserted" or "Deleted" to FALSE, even if a prior file
had set it to TRUE

hmmlib: -std=gnu99

HTML-santitise episode title and project name from templates. This won't
always be correct, but I reckon the common case will require it.

This lets users of Firefox 59+ get sub-millisecond accurate performance:
https://developer.mozilla.org/en-US/docs/Web/API/Performance/now

Don't \-escape anything in the index

Document server's security header (recommended) requirements

We no longer prevent enforcement of strict server security policies (to
be documented)

Add bounds-checking to the Copy string functions, fixing buffer sizes

Fix the marker skipping (e.g. :afk)

Different ISBN database, and slightly more flexible BuildReference()
Permit line-breaking on '/' in the references menu

cinera.css and cinera_player*.js:
More subtle "click here to regain focus" - for @insofaras
Persist theatre mode - for @insofaras
Resume in-progress video at previous timecode - for @AsafGartner

It treats co-hosts and guests differently from chat commenters, styling
and categorising annotations for them such that their contributions
don't come under the "Chat comment" medium

Also do some essentially cosmetic code compression of the marker cases
and other things

cinera_player_pre.js: Make the credits menu initially focus the host's
person if they have no support, rather than the first credited person
who has support

It merely checks the video's privacy status and, if not public, records
its corresponding HMML base filename privately in the .metadata without
generating a player page or a search / table of contents entry for it.
Every four hours it will loop over the .metadata to recheck the privacy
status of any privately recorded entries, and process newly public ones.

Fix template validation to check that the script comes after both the
player and menus (previously it only specified the player).

Fix relocation code to try and remove only the child directories of the
BaseDir, and no shallower (previously it would try and "recursively"
remove directories all the way back to /, obviously not actually getting
there because it would encounter a non-empty directory along the way).

Add "Modes" to the startup printout.

Flags:
    -g Ignore privacy status