Need stderr or equivalent alternative to Info

In some situations informative output gets in the way of desired output (eg, foamDictionary output - EP702).

We can avoid some of this output with argList::noBanner(). In the .org version they have replace this with a dedicated InfoHeader message stream, which handles the same problem. However, we may also to have a more general solution (cf. #881 (closed)). In similar cases it could also be helpful to have a Serr that only outputs on the master.

With dynamic code generation (eg #calc) the process generated copious quantities of output, all of which land on stdout. Perhaps we need a version of system() with a dup2() to redirect.

@Mattijs