The `parse_enum` helper pulls an enum value from the query string
(by delegating down to the parse_string helper with values generated
from the enum).
This is used to pull out "f" and "b" in most places and then we thread
the resulting Direction enum throughout more code.
Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
