.setFields with 'exclude' option with an array of fields to exclude

[oleiba]

This is for setFields as part of squel.update() chaining.
This is useful for when I have an object I am working with, which corresponds to some SQL table schema.
Eventually we would want to do:
squel.update().setFields(obj).toString()
but with the option of excluding some fields from obj.
Obviously, we would prefer a more convenient way than creating an object with a subset of fields every time we would want such functionality.
So eventually we would have squel.update().setFields(obj, {exclude: ['some_field']})

[hiddentao]

Nice work! But why has the change only been made in the built output and not the source code? Plus, tests are needed for PRs.