also remove 'lang' attribute, since it belongs into IQ, see XEP-50 3.7:
"The requester SHOULD provide its locale information using the "xml:lang"
attribute on either the <iq/> (RECOMMENDED) or <command/> element."
instead of using the old baseName=smack appendix=project.name approach,
we are now going convention over configuration and renaming the
subprojects directories to the proper name.
Having a prefix is actually very helpful, because the resulting
libraries will be named like the subproject. And a core-4.0.0-rc1.jar is
not as explicit about what it actually *is* as a
smack-core-4.0.0-rc1.jar.
SMACK-265
