modify tox config to use new validation code

this patch modifies tox.ini to perform both the JSON and YAML validation
checks.

Change-Id: Ie8db699f19dc7698407bab1e3d51dcb6184cfad2

test-requirements.txt

-demjson
+PyYAML

tox.ini

@@ -8,4 +8,5 @@ deps = -r{toxinidir}/test-requirements.txt
 
 [testenv:pep8]
 commands = 
-    {toxinidir}/tools/validate-json.sh
+    {toxinidir}/tools/validate-all-json.sh
+    {toxinidir}/tools/validate-all-yaml.sh