Support Lotus calendars (uses BYMINUTE, BYHOUR, etc.)

[mattcasey]

This library supports all the types of calendars we receive except for those made using Lotus, because it uses BYMINUTE, BYHOUR, or BYMONTH to describe timezones.

How hard would it be to add support for those? I also am willing to patch myself but would appreciate some direction, thanks.

"BEGIN:VCALENDAR
X-LOTUS-CHARSET:UTF-8
VERSION:2.0
PRODID:-//Lotus Development Corporation//NONSGML Notes 9.0.1//EN_S
METHOD:REPLY
BEGIN:VTIMEZONE
TZID:Eastern Standard Time
BEGIN:STANDARD
DTSTART:19501105T020000
TZOFFSETFROM:-0400
TZOFFSETTO:-0500
RRULE:FREQ=YEARLY;BYMINUTE=0;BYHOUR=2;BYDAY=1SU;BYMONTH=11
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19500312T020000
TZOFFSETFROM:-0500
TZOFFSETTO:-0400
RRULE:FREQ=YEARLY;BYMINUTE=0;BYHOUR=2;BYDAY=2SU;BYMONTH=3
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID="Eastern Standard Time":20151028T170000
DTEND;TZID="Eastern Standard Time":20151028T173000
TRANSP:OPAQUE
DTSTAMP:20151019T175722Z
SEQUENCE:4
ATTENDEE;PARTSTAT=ACCEPTED;CN="guest"
;SENT-BY="person2@email.com";RSVP=FALSE
:mailto:person1@email.com
CLASS:PUBLIC
SUMMARY:coffee chat
LOCATION:NY, NY
ORGANIZER;CN="Foo":mailto:foo@bar.com
UID:5619915ff32bff3077c9af0c@calendar.com
X-LOTUS-UPDATE-SEQ:5
X-LOTUS-NOTESVERSION:2
X-LOTUS-NOTICETYPE:A
X-LOTUS-APPTTYPE:3
X-LOTUS-CHILD-UID:0451FEA019239F5600257EE30062A31A
END:VEVENT
END:VCALENDAR"