minor fixes: wombat add document.WB_wombat_location
loaders: file 'urls' starting with . and / are always file paths
pep8 fixes for cdx, utils packages
rewrite fixes: html_rewriter do not unescape attrs!
rules: don't rewrite past end of block or line
better rules.yaml fix
cdx: fix the 'yield nothing' case when limit==1
add additional test case for limit==1 and reverse=True,
as limit is optimized out
cdx: clean up closest, reverse ops
closest takes precedence over reverse
'reverse closest' not supported, add test to reflect that
perms: refactor perms config to make interface much clearer
'perms_policy' is a callback which returns a Perms object, which may
filter cdx lines from the response
perms test: moved test perms policy to perms/test/test_perms_policy.py
all perms related configs exist within perms package