This plugin provides general infrastructure for issuing warnings and
errors upon finding certain regexes. Right now, it just looks to see
that footnotes are formatted with the preceding slash.

The plugin has tests.

Karl called these build strings.  Much better name.

We had fields labelled svn and git, but no real explanation for them
in the string names, so I made them more explicitly refer to the
doctools and ots repos.

After we build a pdf, it is sometimes useful to attach some
information to the built file.  Here we do that as a YAML-formatted
block of lines appended to the PDF and marked in PDF syntax as
comments.  Our PDFs now carry some machine-readable metadata.

If a document comes in and there's no yaml frontmatter, we don't
jinjify.  You might not need any yaml frontmatter metadata but still
want jinja features (e.g. jinja macros).  In that case, add a dummy
var.

The reason for doing this is that legacy docs don't have any
frontmatter, and this is a convenient way to distinguish them.

 * Make -rXXXX versions for all builds, not just drafts
 * Add draft plugin
 * In template, set draft to trigger on both True and 'True'
 * Move path into PIPELINE definition
 * Silence some echo
 * Use .tex instead of intermediate_ltx
 * Simplify some bash
 * Let the plugin handle draft instead of passing it as an option
 * Cleanup .tex files

We can now do redacted and draft at the same time.

Refactor the jinja rendering and the redaction as a pipeline of
filters that run as needed.