Make it clear that event-type-version and schema-url is about 'data' (#48)
Make it clear that event-type-version and schema-url is about 'data' (#48)

Closes #35
Closes #34

Signed-off-by: Doug Davis <ff3bde741799c0eff815b83a54eda3fc494df54f@us.ibm.com>
cloudevents/spec