Added support for pypy

Added support for pypy by changing the wsgi.py to import pyscopg2cffi if pyscopg2 is not available. Added missing dependencies for to the requirements.txt file. Added a pypyenv/ to the .gitignore.

.gitignore

@@ -16,6 +16,7 @@ __pycache__/
 # Distribution / packaging
 .Python
 env/
+pypyenv/
 build/
 develop-eggs/
 dist/

requirements.txt

@@ -10,7 +10,9 @@ coreschema==0.0.4
 idna==2.6
 itypes==1.1.0
 Jinja2==2.9.6
+Logbook==1.1.0
 MarkupSafe==1.0
+marshmallow==2.15.0
 psycopg2==2.7.3.1
 py==1.4.34
 pycparser==2.18

wsgi.py

@@ -1,3 +1,10 @@
+try:
+    import psycopg2
+except ImportError:
+    # Fall back to psycopg2cffi
+    from psycopg2cffi import compat
+    compat.register()
+
 import os
 import sys
 from cookie_api import JSONRenderer, Base, application_factory