* embargo: add support for per-collection date range embargo with embargo options of 'before', 'after', 'newer' and 'older'
'before' and 'after' accept a timestamp
'newer' and 'older' options configured with a dictionary consisting of any combo of 'years', 'months', 'days'
add basic test for each embargo option
* acl/embargo work:
- support acl access value 'allow_ignore_embargo' for overriding embargo
- support 'user' in acl setting, matched with value of 'X-Pywb-ACL-User' header
- support passing through 'X-Pywb-ACL-User' setting to warcserver
- aclmanager: support -u/--user param for adding, removing and matching rules
- tests: add test for 'allow_ignore_embargo', user-specific acl rule matching
* docs: add docs for new embargo system!
* docs: add info on how to configure ACL header with short examples to usage page.
sample-deploy: add examples of configuring X-pywb-ACL-user header based on IP for nginx and apache sample deployments
* docs: fix access control page header, text tweaks
* bump version to 2.6.0b0
* Add unit test to verify whether ACL exact-match rules in a single-line
*.aclj file are found
* Fix AccessChecker to match exact rules in a single-line rule file
- .aclj files contain access controls in reverse sorted, CDXJ-like format
- ./sample_archive/acl contains sample acl files
- directory and single-file acl sources (extend directory aggregator and file index source)
- tests for longest-prefix acl match
- tests for acl applied to collection
- pywb.utils.merge -- merge(..., reverse=True) support for py2.7 (backported from py3.5)
- acl types:
* allow - all allowed
* block - allowed in index (as blocked) but content not allowed, served as 451
* exclude - removed from index and content, served as 404
- warcserver: AccessChecker inited if 'acl_paths' specified in custom collections
- exceptions:
* clean up wbexception, subclasses provide the status code, message loaded automatically
* warcserver handles AccessException with json response (now with 451 status)
* pass status to template to allow custom handling
