Fix autogenerated ops

This developer missed a rather crucial bug in the 'autogen' branch... `Op`s, by design, must not have non-default constructors. At least, it does not make sense for them *not* to have default constructors because the `OpService` will try to instantiate them via no-args constructors and the contract is for `Op`s to have no state apart from the parameters to begin with.

So let's fix the autogenerated `Op`s, let's not generate constructors at all, but instead mark all parameters with the `@Parameter` annotation.

Oh, and while at it, let's make sure that we never commit nor generate `Op`s without default constructors again.