The first batch of changes recommended by the fixdiv tool.  These are
mostly changes of / operators into //.  Once or twice I did more or
less than recommended.
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 6183b0e..f57ba37 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -590,7 +590,7 @@
     filename = getsourcefile(frame)
     lineno = getlineno(frame)
     if context > 0:
-        start = lineno - 1 - context/2
+        start = lineno - 1 - context//2
         try:
             lines, lnum = findsource(frame)
         except IOError: