Implement ason_ns_destroy

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
Add subspaces to namespaces

We can now have namespaces within namespaces, with dot-notation access. So if
we add a namespace to the root called "foo" we can access foo.bar as a
variable.

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
Add unit tests for namespace API

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
Flush stdout when writing test failures

Newline or not, these seem to get lost now and again.

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>