added tests; completed incremental sync

get_page_of_events - returns list of events for a given page; can
turn on/off etag

get_changed_page_urls - returns list of urls for all pages that
have changed since last sync

update_indices - update the indices for all pages that have changed
since last sync
Merge github.com:cfpb/github-wiki-search

Conflicts:
	sync.py
fixed empty events list handling
Merge pull request #2 from dgreisen-cfpb/master

sync
Merge pull request #3 from himedlooff/master

Adds front end files
getting list of all repo_names for indexing
Merge branch 'master' of https://github.com/cfpb/github-wiki-search
Merge pull request #4 from miklane/master

New function sync_all_repos()
Updates querying.