Icalevents

PR merged: Support SEQUENCE in ical events

Initialize default http client for downloader in constructor 61

Fix string "None" being set as summary instead of object None
58 by mabre was merged 8 minutes ago

Add created and last_modified event attributes
57 by mabre was merged 10 minutes ago

Merge pull request 52 from tdaff/no-write-httplib
Disable httplib2 cache when no write permission

Merge pull request 49 from tdaff/rrule-until
Convert RRULE UNTIL with no tzinfo to UTC

added support for default_span adjustment and additional event components 44 by tahouse