Check for Section creation and lookup Directive for Event log.

Conflicts:

	src/ggrc/models/revision.py
Generalize to cover Directive logging when creating Control.
Rename method that generates log json, for clarity.
Override Section, Control so their log dicts show Directive.
Special handling for log jsons with mapped_directive.
Fixup for unicode
Fix Section -> Control and handle Control without Directive
Merge pull request #512 from reciprocity/feature/MapLogFix5

Feature/map log fix5