Merge pull request #646 from cclauss/patch-1

Syntax Error: exec() is a function in Python 3

Author: fredrik-johansson

docs/plots/buildplots.py

@@ -20,4 +20,4 @@
             l = l[:-1] + (", dpi=45, file='%s.png')" % f[:-3])
             code[i] = l
     code = "\n".join(code)
-    exec code
+    exec(code)