Move the .gitignore out of the Marlin subdirectory so it applies to
the whole tree, and add some missing patterns.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Emacs by default doesn't recognise a ".pde" file as C++ source code.
Add the annotation to the top of the file to make it work.
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>