Support for $val === [ {}, $val ] in literal SQL + bind specs

Support for $val === [ {}, $val ] in literal SQL + bind specs

This wraps up the changes started in 0e773352. Now DBIC bind values can
be specified just like the ones for SQL::Abstract as long as no bind
metadata (e.g. datatypes) is needed

Also added an explicit check to catch when a non-scalar non-stringifiable
value is passed without a bind type metadata