Add a debian packaging workflow

This doesn't work on debian.

Fix copyright - my previous PR should have been against master

debian/copyright: avoiding extra "Copyright:"s

Changed my opinion on the debian/* entry since the authors are not a subset.

fix d/copyright

Flesh out copyright, based on feedback from the Debian FTP Masters.

Create d/README.source

d/rules origtarxz: Introduce common root for source tree

And an outreach to the Debian community.

no need to override dh_clean

Preparation for upload to Debian.

This was used to remove non-source files that were used by the Windows
build of mesaflash.  These files were removed from git, so there's no
need to handle them specially when running `debian/rules clean`.

exercise package-building

Fix compiler diagnostics etc

This fixes a diagnostic seen on Ubuntu 10.04 building the examples:

converting a packed 'opd_mode_1_7i77_t' {aka 'struct
opd_mode_1_7i77_struct'} pointer (alignment 1) to a 'u32' {aka 'unsigned int'}
pointer (alignment 4) may result in an unaligned pointer value
[-Werror=address-of-packed-member]

Remove files needed only for Windows

Add daughterboard hints to improve readhmid output

pci_boards: Enable the board before mmap'ing it

This fixes a problem where it was necessary to run linuxcnc first, before
running mesaflash.  This seemed not to affect standard PCs but affected the
CM4.

This can be used to improve the output of `--readhmid` by specifying
daughtercards that are attached at each header.

For example, `mesaflash --device 5i25 --dbname1 7i76`