Federal Administrative and Executive Materials

[jcushman]

This continues work on #48 by adding the "Federal Administrative and Executive Materials" section from the Indigo Book.

As mentioned in #48, this is rife with judgment calls, so I just tried to grind through and get it 90% done. From here we can look for what's missed in cases.

Also in this PR:

• Tests don't run if they're prefixed "text_" apparently.
• I threw in patents and trademarks because I'm curious what comes out! Trademarks just look like "Registration No. 3,886,986" and might turn out to be overinclusive.

[mlissner]

That issue with text_ or something else instead of test_ is coming up enough that I feel like pylint should get on top of it. I keep seeing it!

Thank you for this!