Remember new and already checked but not enabled defines.

 * Recognize already enabled defines from bare Ganako CodeContext.
 * Remember already checked (but not enabled) defines. Currently no
   possibility to force recheck (which e.g. makes sense after installing
   some libraries on system after launching Valama).
Reset cached not available defines with distclean target.
remove_recursively: Improve error messages.

 * Show exactly which file failed with which error.
 * Cmake buildsystem: Show distclean error in build output window.
Update cmake/project.cmake (only indentations).