Refactor the test suite to be python implementation independent

[nick]

An example from pyamf.tests.test_amf3. EncoderTestCase.test_dict:

self._run([
    ({'a': u'a', 'b': u'b', 'c': u'c', 'd': u'd'}, '\n\x0b\x01\x03a\x06\x00\x03c\x06\x02\x03b\x06\x04\x03d\x06\x06\x01')])

The test is specific to the current cPython implementation and other implementations such as Jython fail this test because of the internal ordering of the dict.

A test utility will need to be built that takes the pieces of the amf fragment and checks that against a list. The test cases will need to be altered to fit into this new api.

[thijs]

add reference to jython ticket