Add clang-format file

Also run it across the whole tree to get everything using the One True Style.
We don't yet run this in an automated fashion as it's a little slow, but
there is a snippet to do so in makeall.sh.

LibCore/CDirIterator.cpp

@@ -65,4 +65,3 @@ String CDirIterator::next_path()
     m_next = String();
     return tmp;
 }
-