Update PickerModalViewController to handle iPhone 6/6+ screen sizes (but still work the same on older devices)
Merge pull request #135 from walmartlabs-samsclub/feature/iphone6_PickerModalViewController

Update PickerModalViewController to handle iPhone 6/6+ screen sizes (but...
Make a test and some date math timezone agnostic.

Date math should pretty much never be done in the system time zone, but always
relative to GMT, because of exactly the reasons that were causing this test to
fail. It would work on the west US coast but fail elsewhere, because it just so
happened to use the correct 7hr GMT offset in the test dates. Using the system
time zone would result in a "shift" from the given dates to the calculated
date of the difference of the time zone in which the test was being run to PST.