Pubsub: increase CSV max field.

feed can be *very* large.

slapos/pubsub/__init__.py

-from datetime import datetime
+import argparse
 import csv
 import feedparser
+import httplib # To avoid magic numbers
 import io
-import socket
 import json
-import time
 import math
-import httplib # To avoid magic numbers
-import argparse
 import os
+import socket
+import sys
+import time
+from datetime import datetime
 from hashlib import sha512
 
 from atomize import Entry
@@ -19,6 +20,9 @@ from flask import abort
 from flask import request
 app = Flask(__name__)
 
+# csv entries can be very large, increase limit.
+csv.field_size_limit(sys.maxsize)
+
 @app.route('/get/<feed>')
 def get_feed(feed):
   global app