In HTML, the line break immediately following a start tag is ignored
(see: https://www.w3.org/TR/html4/appendix/notes.html#h-B.3.1). An
extra span tag has been introduced in the upstream Pygments
HtmlFormatter in order to preserve the first new line. The Bugdown
Tests as well as our fenced_code.js frontend markdown processor have
been updated to reflect this new behavior.
These tests would work as part of the whole suite, but
not standalone, because they were getting objects out
of node's require cache that a previous test had cleaned up.
Now they should work standalone as well, and the tests
are more explicit about their dependencies.