Added --get-selections and --set-selections. This allows you to save the
current set of chosen implementations for use later.
Note: --get-selections doesn't yet work when the GUI is used. The plan is
to have the GUI return the set of selections to the main 0launch process
in all cases, rather than having it exec the program itself. This is so that
a program running in a sandbox (without write access to the cache) can use a
more privileged GUI process to download required components.
git-svn-id: file:///home/talex/Backups/sf.net/Subversion/zero-install/trunk/0launch@1649 9f8c893c-44ee-0310-b757-c8ca8341c71e