...since it does quite a bit more than only preprocessing, as the name
suggests. We use that class to process source files in general. The
output is not a preprocessed source, but a set of CPlusPlus::Documents
with symbols.

Change-Id: I787d0f22f9f042ddf0c99e8c2f0bdb9aa7001735
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>