Nightly: better not to make shell scripts executable (#514).

Because then they can be run remotely, as they are
in the cgi-bin directory.
Nightly: fix hashbang line in webapp.
Nightly: make sure webapp works on our server (#514).

- Need CGI module
- Work as CGI, unless hostname ends with .local. Previous
  detection based on .com hostnames did not work, not sure why.
Nightly: webapp: fix download URLs (#514).
Nightly: better test data, it is actually meaningful (#514).