drop optional simplejson requirement

The json module in standard lib from python2.7 onward is good enough.
This change also removes the surprise since the setup.py will not
require simplejson if json is present, but at runtime simplejson is
preferred if it exists.

pecan/jsonify.py

@@ -1,10 +1,6 @@
-try:
-    from simplejson import JSONEncoder
-except ImportError:                     # pragma: no cover
-    from json import JSONEncoder        # noqa
-
 from datetime import datetime, date
 from decimal import Decimal
+from json import JSONEncoder
 
 # depending on the version WebOb might have 2 types of dicts
 try:

pecan/tests/test_base.py

@@ -1922,11 +1922,6 @@ def index(self, name='Jonathan'):
         assert 'support for "mako3" was not found;' in str(expected)
 
     def test_json(self):
-        try:
-            from simplejson import loads
-        except:
-            from json import loads  # noqa
-
         expected_result = dict(
             name='Jonathan',
             age=30, nested=dict(works=True)
@@ -1940,7 +1935,7 @@ def index(self):
         app = TestApp(Pecan(RootController()))
         r = app.get('/')
         assert r.status_int == 200
-        result = dict(loads(r.body.decode()))
+        result = json.loads(r.body.decode())
         assert result == expected_result
 
     def test_custom_renderer(self):

pecan/tests/test_generic.py

@@ -1,8 +1,5 @@
+from json import dumps
 from webtest import TestApp
-try:
-    from simplejson import dumps
-except:
-    from json import dumps  # noqa
 
 from six import b as b_
 

pecan/tests/test_jsonify.py

@@ -1,9 +1,6 @@
 from datetime import datetime, date
 from decimal import Decimal
-try:
-    from simplejson import loads
-except:
-    from json import loads  # noqa
+from json import loads
 try:
     from sqlalchemy import orm, schema, types
     from sqlalchemy.engine import create_engine

pecan/tests/test_rest.py

@@ -1,15 +1,11 @@
 # -*- coding: utf-8 -*-
 
+from json import dumps, loads
 import unittest
 import struct
 import sys
 import warnings
 
-try:
-    from simplejson import dumps, loads
-except:
-    from json import dumps, loads  # noqa
-
 from six import b as b_, PY3
 from webtest import TestApp
 

setup.py

@@ -14,14 +14,6 @@
         if (line and not line.startswith('-'))
     ]
 
-try:
-    import json  # noqa
-except:
-    try:
-        import simplejson  # noqa
-    except:
-        requirements.append("simplejson >= 2.1.1")
-
 try:
     from functools import singledispatch  # noqa
 except: