Fix compatibility with Django < 1.8

The 1.6.1 release added a dependency on the `setting_changed` signal. In Django
releases prior to 1.8, this signal is located in the `django.test.signals`
module, and in 1.8, an alias was added in `django.core.signals`.

This change adds a fallback import to restore compatibility with older versions
for applications which cannot (yet) migrate to the newer Djangos. It has been
tested against Django 1.6.11 and 1.8.9.

add doc for deactivate collector in develop

adding the ability to disable the collector in develop

This reverts commit 7520777f.

This reverts commit f05fe5e5.

Names on disk and config files should not have to be safe for shells to
interpret. As close to possible, we should take literals and give literals to
the OS kernel to operate on directly. For filename globs, it is our
responsiblility to expand them, and if we had no problem with backwards
compatibility, we would insist config files' SCRIPT_ARGUMENTS parameters are
tuples of discrete values. Delegating those to a shell breaks clear boundaries
of interpreetation and will always be prone to errors, oversight, and
incompatibility.

So, now, we never take names that are unsafe and try to make then safe for a
shell, because we don't need a shell.

This fixes #444, which had problems with Windows paths being insensible to the
crazy quoting we hoped would make a filename safe for a shell.

This fixes #494, which had a compiler-attempt stdout captured as part of a
string interpreted by a shell. When the compiler didn't exist, that shell
expression STILL created empty files, and the pipeline thenafter served an
empty file as if it were real compiler output.

Fix literal markup for settings

Remove unnecessary indentation

To avoid wrapping text in `<blockquote>` tags.

In headings and one non-heading. This is probably a leftover
after some semi-automated way of removing that `PIPELINE_` prefix.

Added password for jazzband PyPI user account.

Fixes https://github.com/jazzband/roadies/issues/3.