Rename the 'tests' directory to 'ipa-tests', and create an ipa-tests RPM
containing the test suite

Part of the work for: https://fedorahosted.org/freeipa/ticket/3654

Several Commands were missing the 'version' option. Add it to those
that were missing it.

Do not remove the version option before calling commands. This means
methods such as execute(), forward(), run() receive it.
Several of these needed `**options` added to their signatures.
Commands in the Cert plugin passed any unknown options to the underlying
functions, these are changed to pass what's needed explicitly.
Some commands in DNS and Batch plugins now pass version to commands
they call.

When the option is not given, fill it in automatically. (In a subsequent
commit, a warning will be added in this case).

Note that the public API did not change: all RPC calls already accepted
a version option. There's no need for an API version bump (even though
API.txt changes substantially).

Design page: http://freeipa.org/page/V3/Messages
Tickets:
  https://fedorahosted.org/freeipa/ticket/2732
  https://fedorahosted.org/freeipa/ticket/3294

The changes include:
 * Change license blobs in source files to mention GPLv3+ not GPLv2 only
 * Add GPLv3+ license text
 * Package COPYING not LICENSE as the license blobs (even the old ones)
   mention COPYING specifically, it is also more common, I think

 https://fedorahosted.org/freeipa/ticket/239

Before the patch that allows to create unshared instances of Connectible
objects, all Connection object were deleted at once in destroy_context().
It made sense at the time, because there was always at most one Connection
per Connectible subclass and Connectible.disconnect() was called only
internally by the Executioner class. Now that we can make arbitrary
connections, it makes more sense to delete the Connection object when
Connectible.disconnect() is called.