Stop fec crashes

Add tests and fixes for:

18F/openFEC#202 - Fix 11 CFR 110 Table of Contents
Correctly parse '<AMDPAR>5. Section 100.94 is added to subpart C to read as follows:</AMDPAR>'
Handle lack of section_by_section stemming from lack of full text XML notice.
I think I understand why this is needed, but a comment would make it clear. Also, you can combine this nested if with an `and`