tests: Add a test for multiple sections per comment block

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Don't eat newlines in section heading regex

Use a lookbehind operator to match the newlines without stealing them.
Fixes test in previous commit.

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Add some newlines to space out the output a bit

https://bugzilla.gnome.org/show_bug.cgi?id=723288
tests: add test for section heading without trailing hash

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Support leaving off the trailing hashes in headings

Fixes test added in previous commit.

https://bugzilla.gnome.org/show_bug.cgi?id=723288
tests: add test case for second level heading

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Don't identify ## level headings as first level

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Use a slightly more robust way of keeping track of markdown tags

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Support refsect3 markdown

https://bugzilla.gnome.org/show_bug.cgi?id=723288
tests: add a test case for not change existing lists

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Make the parsing of lists a bit more robust

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Add more markdown-style list support (*)

https://bugzilla.gnome.org/show_bug.cgi?id=723288
Support lists with blocks inside them

https://bugzilla.gnome.org/show_bug.cgi?id=723288
tests: add test case for an example block in an ordered list