Merge 'issue_73' into development: closing issue #73 (exclude spec tests)

The spec tests are now excluded from nosetests, by default.  Added
instructions to the README on how to include them.

README.rst

@@ -71,6 +71,7 @@ To include tests from the mustache spec_ in your test runs: ::
 
     git submodule init
     git submodule update
+    nosetests -i spec
 
 
 Mailing List

tests/test_spec.py → tests/spec_cases.py

 # coding: utf-8
 
 """
-Tests the mustache spec test cases.
+Creates a unittest.TestCase for the tests defined in the mustache spec.
+
+We did not call this file something like "test_spec.py" to avoid matching
+nosetests's default regular expression "(?:^|[\b_\./-])[Tt]est".
+This allows us to exclude the spec test cases by default when running
+nosetests.  To include the spec tests, one can use the following option,
+for example--
+
+    nosetests -i spec
 
 """
 
 import glob
 import os.path
+import sys
 import unittest
 import yaml