Do not remove doc/ during `make clean`: it contains the manpages

Signed-off-by: Christophe Vu-Brugier <cvubrugier@fastmail.fm>
debian: add binaries to Python 2 installed files

Signed-off-by: Christophe Vu-Brugier <cvubrugier@fastmail.fm>
debian: install manpages

Signed-off-by: Christophe Vu-Brugier <cvubrugier@fastmail.fm>