Adding ipython to requirements

We had this before as a python dependency but it was dropped when we switched to virtual environments

Adding ipython to requirements
8aebb14e · John Jarvis · df578de1 · 8aebb14e
Commit 8aebb14e authored 12 years ago by John Jarvis
--- a/requirements.txt
+++ b/requirements.txt
@@ -55,3 +55,4 @@ dogstatsd-python
 # MySQL-python
 sphinx
 Shapely
+ipython