Line 881 - The "optionality" of dtEnd and duration is not clearly defined

Changed section to no longer redefine Vavailability (and Avaialability), but too instead merely describe their use in as a Component in Gluons in WS-Calendar. An additional use for gluons is to expose a Sequence for remote invocation. The service offered may be only sometimes available. WS-Calendar incorporates the iCalendar extension [Vavailability] to expose this schedule. [Vavailability] offers a means to describe recurring temporal patterns, such a weekdays from 9:00-5:00, Thursday mornings until July, and thereafter Tuesday evening as well. A Vavailability component is a collection of Availability components, each with its data boundaries and its recurrence patterns. The parameters and properties are those defined in iCalendar, the structure is defined in the referenced [Vavailability] , and the artifact is an optional Component of a Gluon. A requestor may not be aware of all aspects of the Sequence. A service requestor does know, however, the desired Start and Duration of the Designated Interval. [Vavailability] . In a Gluon is interpreted as a filter on the Designated Interval, but on no others. WS-Calendar adds a single optional parameter to the [Vavailability] component. When a Granularity component is applied, it further defines the acceptable service invocation. Granularity is discussed in the next section.