Have qfetch prepend RecName_ to the query name

This will reduce repetition and align the query name with that specified
in the record behaviour module.
Add gen_fetch, gen_delete query generators to exports

These functions can be useful for generating custom queries.

gen_fetch (renamed from gen_fetch_by) is enhanced to generate a multiple
"by" if a list of atoms is passed in. A query with multiple ANDs in the
WHERE clause is generated.

Also improving test coverage.
Merge branch 'sf/gen_fetch2'