Update to version 2.7.0

This version fixes a problem that only affected getopt_long() on Linux
(or rather, the GLIBC implementation) by replacing its use by optparse().

In addition, this version features a PRNG that can be used to generate
arbitrary length pseudo-random numbers and 5 new translations (for Dutch,
Japanese, Polish, Russian, and Simplified Chinese).

These translations have been generated and verified with online tools
(https://www.deepl.com/translator and https://translate.google.com)
and might therefore not be fully correct - a review by native speakers
would be appreciated.

Approved by: antoine (implicit)