Remove tag subscriber updates from inner write loop

[Aaronontheweb]

Should we get rid of the tag subscribers stuff inside the write loop? Seems out of place given that we still have to poll for changes on the table to detect changes that happen exclusively on other nodes in the network. This is something that got copied and pasted into a lot of journals but it was only ever really appropriate for SQLite / in-memory.

Originally posted by @Aaronontheweb in #207 (comment)