dropped a table by mistake

[adamfoneil]

Yesterday I dropped a large table in a dev database full of zip codes that I had staged for loading into another table.
Because the table didn't map to a model class, ModelSync wanted to delete it, which is the defined behavior.
But when a table has data, it should be harder to drop:

• I think the row count should appear in the table node so you can see how much data you're about to drop.
• It should come up automatically as a shared exclusion that you have to include manually if you want ModelSync to drop it.