Progress-like output to stderr, final output line to stdout

[HenrikBengtsson]

In order to make it easier to redirect displayed results, while yet showing progress-like output while processing, output the latter to stderr, and the final string for each line to stdout.

Currently, we output everything to stdout, which when redirected to file will produce files with:

- future() - conditions^M\ future() - conditions (1/1)^MM-bM-^\M-^T future() - conditions (1 test) (56ms)$
- %<-% - conditions^M\ %<-% - conditions (1/1)^MM-bM-^\M-^T %<-% - conditions (1 test) (9ms)$
- Argument '...'^M\ Argument '...' (1/1)^MM-bM-^\M-^T Argument '...' (1 test) (9ms)$

With this proposal, redirecting stdout would produce:

- future() - conditions (1 test) (56ms)$
- %<-% - conditions (1 test) (9ms)$
- Argument '...' (1 test) (9ms)$