Small set of improvements

35b32eb addresses the issue, I came across that while AGScopeBarItems can be disabled, if they are collapsed they are not.
a9e8712 addresses an issue I had with the AGScopeBar in which tile was repeatedly called causing constant ~30% cpu utilization.
3112ba7 finally just adds a prod spec file. So that AGScopeBar can be used more easily in combination with CocoaPods.

Finally I kindly would like to request that the license would be made more explicit. MIT license seems to be very close in intent to the current license string.