Handle None initial values more robustly.

Signed-off-by: Antoine Catton <acatton@fusionbox.com>
(cherry picked from commit 8e3483b7dab0fdb09fffee6d85d172155d6b8dbe)
Added CHANGES for 1.0.1

(cherry picked from commit 08d8a65ea19cf3f56b4dddbdaac25bd6b2236c6a)