Revert swig version back to 3.0.2 and add test checking network parameters

[lscheinkman]

When installing the latest versions of nupic and nupic.core directly from master the test unified_py_parameter_test/testScalars fails with the following error:

self = <tests.unit.nupic.engine.unified_py_parameter_test.NetworkUnifiedPyParameterTest testMethod=testScalars>

    def testScalars(self):
      scalars = [
        ("int32Param", 32, int, 35),
        ("uint32Param", 33, int, 36),
        ("int64Param", 64, long, 74),
        ("uint64Param", 65, long, 75),
        ("real32Param", 32.1, float, 33.1),
        ("real64Param", 64.1, float, 65.1),
        ("stringParam", "nodespec value", str, "new value")]
    
      n = Network()
      l1= n.addRegion("l1", "TestNode", "")
      x = l1.getParameter("uint32Param")
    
      for paramName, initval, paramtype, newval in scalars:
        # Check the initial value for each parameter.
        x = l1.getParameter(paramName)
>       self.assertEqual(type(x), paramtype, paramName)
E       AssertionError: <type 'int'> != <type 'long'> : int64Param

Using git bisect I was able to pinpoint the issue to the the latest swig update.

This PR is reverting swig back to version 3.0.2 and adding a test similar to testScalars test to nupic.core so we could catch issues similar to this sooner.

@rhyolight Please review

[rhyolight]

@breznak Luiz found that #1321 introduced a bug (perhaps in the new swig version, perhaps because of how we are using it). There is a test in NuPIC that found the bug. This PR moves the test here into nupic.core instead (where it should be), but the test fails as described above unless we revert back to swig 3.0.2.

Once this is merged, I will re-open #1293 and we can talk about what happened and how to get swig updated again if you like Marek.