To override all child pages

Closes #397
Tests from PR #434

Can't remember why it was doing that even
with the comment and the test added in the
commit still pass so...

Fix #462

Fix #430

Fix #383

Closes #403

As mentioned in #376

Push summary handling into Markdown parsing, identifying the presence
of one by giving its length in the rendered markup.

Hopefully a better fix for #376.

Also fix tests

Close #367, #372

Close #115

Closes #228
Closes #229

This removes the dependency cycle between config and rendering that
causes 4 packages to be recompiled every time a change is made.

I just want to code fast!