DTV_ — invalid indexical time references

The definitions of the indexical time intervals in clause 15 include references to time point concepts that either do not exist or are not visible in the included vocabularies. These concepts include:

day of year (which does not exist)
hour of day (in clause 13, which is not included in clause 15)
minute of hour (in clause 13, which is not included in clause 15)
calendar week (in clause 12, which is not included in clause 15)
week period (in clause 12, which is not included in clause 15)

Recommendation: define 'day of year' in clause 10.2, and move the other concepts from their current locations to clause 10.2.

The structure of the Date-Time Vocabulary is revised to make the Indexical Time Vocabulary include the vocabularies that define these concepts, thus resolving the issue. The reference to 'day of year' is corrected to reference 'Gregorian day of year'.