cdx: add domain-specific rules at cdx layer for custom canonicalization!
and 'fuzzy' matching when not found
handled via cdxdomainspecific.py
BaseCDXServer contains a canonicalizer object and a fuzzy query
canonicalizer abstracted to seperate class (in canonicalizer.py)
clean up cdx related exceptions
default rules read from cdx/rules.yaml
filename configurable via 'domain_specific_rules' setting in config.yaml
fix typo in pywb/rewrite