Platform.Console: run console init code only on windows (via #idef)

On all non-windows platforms the project is now free from C code.
Lib.PPrint: unified 'indentation' and 'spaces'
Lib.PPrint: removed dependency on OverloadedStrings
Main: code formatting
Compiler.Compile: documented 'Terminal'
Common.IOErr: factored out from 'Compiler.Compile'