[RIF] Action-708 - Add import rejection test category to test cases and add combination constant equivalence test case

Dear WG,

I added a section in the test document:
    http://www.w3.org/2005/rules/wiki/Test#Import_Rejection_Tests

and made the following test case changes:

   1. in the PositiveEntailment test [1], changed the syntax of the iris in
the RDF imported graph and RIF conclusion
         import:        "http://b"^^rif:iri <http://b%22%5E%5Erif:iri> --> <
http://b>
         conclusion:  <http://b> -->
"http://b"^^rif:iri<http://b%22%5E%5Erif:iri>

   2. changed [2] & [3] from PositiveEntailment to ImportRejection tests and
changed their names from
RDF_Combination_Constant_Equivalence_Graph_Entailment_[1 & 3] to
RDF_Combination_Invalid_Constant_[1 & 2]

   3. added a couple new ImportRejection tests, [4], [5]

Stella

[1] http://www.w3.org/2005/rules/wiki/RDF_Combination_Constant_Equivalence_1
[2] http://www.w3.org/2005/rules/wiki/RDF_Combination_Invalid_Constant_1
[3] http://www.w3.org/2005/rules/wiki/RDF_Combination_Invalid_Constant_2
[4] http://www.w3.org/2005/rules/wiki/RDF_Combination_Invalid_Profiles_1
[5] http://www.w3.org/2005/rules/wiki/OWL_Combination_Invalid_DL_Formula