SDK:Generate UUID for Extensions
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Windows
There is a build-in tool "Create GUID" in Microsoft(r) VisualStudio that generates GUIDs: http://msdn2.microsoft.com/en-us/library/aa475087.aspx
Mac
On Mac, you can use the online tool: http://uuid.deersoft.de
or one can use the command line tool uuidgen to generate a UUID (in a slightly different presentation however).