Better defaults (doExactConfig = true; doHaddock = true; non-reinstallable lib:ghc)

[angerman]

Fixes #201, #191

[angerman]

This will sadly cause a mass-rebuild. Let's see what breaks!

[angerman]

Ok, this just won't work for now as cabal screws with sublibs. It seems to be impossible to get exact-configuration + cabal_config to work with sublibs. I'll bang my head against this a bit more, but may give up.

[angerman]

@rvl convinced me that we do want haddocks to be the default.

[klarkc]

@angerman what was the argument? Just to see if worth it to keep it enabled (it doubles the number of building packages here).

[angerman]

@klarkc I'm afraid I don't completely recall the argument anymore. I think it was due to haddocks not being available at when disabled.

Do you have a specific reason for the inverse default?

[klarkc]

@angerman no specific reason, just trying to optimize build times.

[angerman]

To optimize buildtimes cur everything you don't absolutely need :-)