[dependencies] Use psycopg2-binary as recommended

This avoids the need to build the psycopg2 packages and thus requires
PostgreSQL dependencies.

buildout.cfg

@@ -64,7 +64,7 @@ eggs = alabaster
        pip
        psutil
        ptyprocess
-       psycopg2
+       psycopg2-binary
        Pygments
        pyparsing
        python-archive

setup.py

@@ -61,7 +61,7 @@ setup(
         "docutils",
         "Jinja2",
         "nose",
-        "psycopg2",
+        "psycopg2-binary",
         "pytz",
         "psutil",
         "setuptools",