Test case for #31.
Apparently `TEST_AFTER_BUILD` doesn’t work anymore. Yay!
Added a destination specifier for iOS, so that xcodebuild doesn’t assume I want to run on a device that isn’t present.
Wrap the time-zone cache in an object that stores it in the thread dictionary. Should improve thread safety and thereby fix #12. (However, I have not tested it in a multi-threaded situation.)
Added test-case for Issue #36
Fixed Issue #36
Merge pull request #40 from iOSCowboy/Issue-36

Fix for Issue #36