Ingest PA repeat flag for all channels

Simplifies the interpretation of the Broadcast _repeat_ flag for PA
data. A PA 'yes' flag is ingested as a repeat for __all__ channels. A PA
'no' flag or a missing flag is interpreted as `null`. The rational is a
'yes' flag is _definitely_ a repeat, anything else we can't be sure.
Check repeat flag setting in test
Merge pull request #265 from atlasapi/mbst-5414-pa-repeat-flag

Ingest PA repeat flag for all channels