Support ancient long arguments; bump to 10.1.1

Because it was a good idea in 1980-something, get_message
is in lots of places with non-GNU-style long arguments.  Include
a dumb hack to support these.

Also, support the -z argument, while noting that it's deprecated.

Release this as 10.1.1
Merge branch 'master' into debian
Package 10.1.1; create cache directory

- Package 10.1.1 with usptream fixes for long arguments
- Create the cache directory
- Add a prerm to delete the messages file upon removal, so
  that dpkg will delete the directory.