Fixed plurality error in DescribeTimeSpan

(It was reporting "1 hrs" instead of "1 hr")

Also, copyright year updated to 2013

Version changed to 0.2.10
Updated to .NET 4.5

* Added the static method Json.Copy

Version changed to 0.3.1.0
Fixed Commmon.Functions.Repeat

* Also, added a simple unit test for it

Version changed to 0.3.3.0