Fixed a bug in the full URL generation.

For some reason, it was pasting the path and the source filename
together with a hyphen between them.
plugins/unpack-generic.plugin: made it able to unpack xz files.

Actually, took advantage of tar's ability to figure out how a file
is compressed for itself, and merged all of the different kinds of
tar unpack to a single command line.
unpack-generic.plugin: Reinstated zip file support, whoops
fix expand_alias with NEVER_ASK=1

Even if we shouldn't interact with the user, we should still
resolve the alias if we already know a value for it.

Please merge and push a bugfix release!
This bug removes all stored optional_depends selections
for aliases with each `lin moonbase`.
Merge pull request #96 from v4hn/fix_expand_alias

fix expand_alias with NEVER_ASK=1
Merge pull request #88 from dagbrown/fix-full-url

Fixed a bug in the full URL generation.
Merge pull request #91 from dagbrown/tar_automatic_detection

plugins/unpack-generic.plugin: made it able to unpack xz files.
Version 13

Bug fix release and minor tweaks. Fixes one major bug with the new expand_alias code that
caused optional_depends questions to be asked again.