Rebuild squidge to make comp mode selection work

The squidge binary was mysteriously about 8 times too small.
Presumably it had been built in the wrong environment (it wasn't
stripped, so it wasn't that).  For some reason the comp/dev mode and
zone selection stuff didn't work with this smaller binary.  Who knows
why.

This patch replaces the squidge binary with a rebuild of it, again
from c6959cc3af2fadf09834b8d8aca5d4a50e83d39a in squidge.git.  This
actually works properly.
Fix competition mode marker offset transparency.

In competition mode, the offset for the competition mode markers was not being
taken away from the absolute codes. This has probably not been noticed because
most people use the relative marker offsets instead of absolute marker numbers
- the bug has existed from the start.

Could this be why I've heard anecdotal evidence of a few robots failing
to detect markers last year?

This patch set was actually tested, unlike the first.

Change-Id: I3ed0c7abcfee19c008ebd9abe93263a783798ecd
Specify the search directory in 'find'

GNU's find works without specifying the search directory, but this is
not standard behaviour - others (such as the BSD equivalent) abort.
Add an option to disable binary stripping

This involves a little jiggling to replace the previous ad-hoc options
parsing with argparse.

readelf isn't (easily?) available on Darwin, which was previously a
barrier to make-zip's use on that platform - this command line option
to disable binary stripping, which is documented as optional, avoids
the issue.

Change-Id: Iea9bb31462335f5705f8baada93c46ace2118d71