Fix note syntax usage.

http://sphinx.readthedocs.org/en/latest/markup/para.html?highlight=note#directive-note
Merge pull request #1818 from ericholscher/small-doc-fix

Fix note syntax usage.
Fixed test that reads a migration file from disk.

We need to make sure content read from the file is decoded from UTF-8
right from the start so Python doesn't try to use another encoding
(read: ASCII/CP1252 under Windows.)
Rearranged some file-related tests

Just moving around some tests to be more logically grouped.