Rebuild calendar algorithm to use Google Calendar API

The !next and !nextfan commands will now pull the list of events from
the Google Calendar API, which should make them a lot more accurate
going forward.

Also... added a !nextfan command.

Remove icalendar from dependencies, as we don't need it any more. Also
remove the version restriction on python-dateutil, as we don't need that
hack monkey-patch for dateutil.rrule any more.
Fix help formatting
Fix nextfan command
remove !wiki
remove !#d#
`storage.find_game` can be used with a string
Revert "Milestone update"

This reverts commit c201ec0dc39a3511195d21fcecd135d1a0ecc520.
Pylint suggested changes; remove unnecessary shebangs.

pylint command line: pylint -d mixed-indentation,anomalous-backslash-in-string,missing-docstring,invalid-name,cyclic-import,line-too-long,unused-argument,redefined-outer-name,too-many-arguments,bad-continuation,unbalanced-tuple-packing,logging-not-lazy,bare-except,no-self-use,maybe-no-member,unbalanced-tuple-unpacking,broad-except,dangerous-default-value,too-few-public-methods,fixme,no-member,star-args,too-many-public-methods,too-many-instance-attributes,too-many-branches,unused-variable,global-variable-undefined,protected-access,import-error,bad-builtin,raising-bad-type *.py