"Hybrid" compiler server.

It would be nice if one could use the server in a hybrid mode that uses the cache only for display/diagnostics and is ignored in any build (if the build succeeds, it should replace the cache used by IDE services). Motivation:

1. The most obvious one is that one may be using macros that don't play well with the server. Of course as I'm sure @Gama11 would point out if didn't: the long term solution here is to fix such macros and/or report compiler issues if it can be reduced to something in the compiler. This is not always practical though.
2. Fully deterministic builds. Things get typed in the same order. Any incremental ids one may generate wind up in a stable order (at least for local changes).