Cleaned up date_ical_format_text(), other bugfixes.
date_ical_format_text() was going way overboard on it's attempts
to make text iCal compliant. I got rid of all the escaping, and also
all the extra endlines which the drupal function was adding at 80-char
boundries.
I added the summary_field option to option_definition, which should
fix several (surprisingly unreported) errors related to Features and first-time
setup.
Added the view object as a parameter for theme_date_ical_icon, which gives
additional context for any module that would like to override that theme.
