Import regression tests from Neubot 0.4.15.7

Before importing the tests, I automatically updated the
version number from 0.4.15.7 to 0.4.16.8.
debian.mk: change regress find(1) -perm to be more liberal

This cherry-picks and adapts the following commit into the
neubot_debian repository:

    https://github.com/neubot/neubot/commit/fe5c75d010f0
Merge branch 'master' of github.com:neubot/neubot_debian

Conflicts:
	debian.mk