processor.py: Fixes minor _parse_url() log formatting.
processor.py: Makes _parse_url() classmethod.
url.py: Adds percent-encoding normalization.

Normalize paths and query strings. Percent-encoding escapes are
uppercased. Adds uppercase_percent_encoding(), split_query(). Backports
qoute functions from urllib.parse.
writer.py: Uses url.qoute instead.