Simplifying the engine a bit

Clearly the ackwardness of using sql sequences directly into result is overcoming the future of the engine. I propose the sollowing, sql sequences assigned to operators do too write to reul, rather they perform a select and deliver the row to the engine, at in:
select key,link,pointer, and other variables where match and rowid conditions are met on other and self;

Deliver the data, and we put the g function in the general call back, and let it reform the result maintain pointers and write result. Much better control, allows arbitrary square tables with schema, and so forth. I will make that happen right away.

Done, everything now uses call backs, and it dropped another 20 lies of code fro the engine, but it expects more c call back code for managing the output flow to result from the ongoing process.