When unknown keyword arguments are passed to a Command, raise an
error instead of ignoring them.

Options used when IPA calls its commands internally are listed
in a new Command attribute called internal_options, and allowed.

Previous patches (0b01751c, c45174d6, c5689e7f) made IPA not use
unknown keyword arguments in its own commands and tests, but since
that some violations were reintroduced in permission_find and tests.
Fix those.

Tests included; both a frontend unittest and a XML-RPC test via the
ping plugin (which was untested previously).

https://fedorahosted.org/freeipa/ticket/2509

dnsrecord_add interactive mode did not work correctly when more
than one DNS record part was entered as command line option. It
asked for remaining options more than once. This patch fixes
this situation and also adds tests to cover this use case
properly.

https://fedorahosted.org/freeipa/ticket/2641

Currently, each DNS test case first checks if DNS is configured
by creating and deleting a test zone. This takes quite a lot of time.

This patch moves the check to the setUpClass method, so the check is
only done once for all the tests.

Similarly, if the server is not available, entire XMLRPC test classes
are now skipped.

Additionally, CLItests that hit the server are skipped if the server
isn't available.

These test that command lines are parsed to correct Command arguments.
Includes some tests for interactive prompts.

To make this possible cli.run is broken up into several pieces.

We have a larger goal of replacing all DN creation via string
formatting/concatenation with DN object operations because string
operations are not a safe way to form a DN nor to compare a DN. This
work needs to be broken into smaller chunks for easier review and
testing.

Addressing the unit tests first makes sense because we don't want to
be modifying both the core code and the tests used to verify the core
code simultaneously. If we modify the unittests first with existing
core code and no regressions are found then we can move on to
modifying parts of the core code with the belief the unittests can
validate the changes in the core code. Also by doing the unittests
first we also help to validate the DN objects are working correctly
(although they do have an extensive unittest).

The fundamental changes are:

* replace string substitution & concatenation with DN object
  constructor

* when comparing dn's the comparision is done after promotion
  to a DN object, then two DN objects are compared

* when a list of string dn's are to be compared a new list is
  formed where each string dn is replaced by a DN object

* because the unittest framework accepts a complex data structure of
  expected values where dn's are represeted as strings the unittest
  needs to express the expected value of a dn as a callable object
  (e.g. a lambda expression) which promotes the dn string to a DN
  object in order to do the comparision.

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

This also requires a resolvable hostname on services as well. I want
people to think long and hard about adding things that aren't resolvable.

The cert plugin can automatically create services on the user's behalf when
issuing a cert. It will always set the force flag to True.

We use a lot of made-up host names in the test system, all of which require
the force flag now.

ticket #25