Change in behavior for integer

[stevenou]

In versions prior to 2.9.0, one could set an integer setting to nil (or not set it at all). Now, due to deserialize method that forces to_i, a nil value deserializes to 0 instead of nil.

Therefore, it breaks any code checking for nil setting. I believe nil should be a legitimate value that should be allowed for an integer setting.

[huacnlee]

Just released v2.9.2 to fix this issue.