Explictly select python 3. The `python2` and `python` packages will
be removed from Ubuntu. Until each call site is fixed, install a
/usr/local/bin/python symbolic link as a non-intrusive work-around
(.deb packages do not interfer with /usr/local).
Add an explicit maintainer for bbc-basic.
Undo some cosmetic changes in order to reduce the global diff, this
merge request will probably be sqashed before acceptance.
Move lib{readline,edit}-dev out of the generic part.
Use existing .deb packages for GHDL and vim.
