--preprocess option no longer supported?

[rpgoldman]

I tried to use the --preprocess and --pp-output-file options to smtrat-shared after a new build and got the following error:

ERROR smtrat: This version of SMT-RAT was compiled without support for stand-alone preprocessing.

Was this change intended? It's problematic because it makes it much harder to investigate issues such as #108

[rpgoldman]

Looks like I need to do the following now:

cmake -DCLI_ENABLE_PREPROCESSOR=ON ..

I urge you to restore the ON setting as a default -- it's very useful and the default being OFF can be quite confusing since the relevant flags are not dropped from the --help output.

[derjasper]

We will add some hints to the cmake options.