Update rss2ical.php

done: find alternative to [webservice](http://subversion.assembla.com/svn/ejm/include-both/rss2icalinc.php)
done: make filetype ics plaintext via htaccess
done: make LF to CRLF, [see RFC](http://tools.ietf.org/html/rfc2445#section-4.1)
done: make version first property
done: remove oldfashioned erronious variable declarations for get
done: adding parameter for Disposition
done: splitting description by 75th char per line
done: optional linewrap for description
check for undefined variables
support start and end time
support time zones
validate with calendar software (finally make it work with e.g. google calendar)