Remove dependency on jsonpatch and jsonpointer

It's not clear at all why these were ever in the requirements
list, because they're not imported, and they don't appear to be
an upstream dependency of jsonschema.

Author: cwacek

requirements.txt

@@ -1,7 +1,5 @@
 Markdown==2.4
 inflection==0.2.0
-jsonpatch==1.13
-jsonpointer==1.10
 jsonschema==2.3.0
 pandocfilters==1.2
 six>=1.5.2