Added new theme for NativeListDialog: IOS_PICKER_THEME that will allows a popup display with a  picker instead of a android style list.
* Made Cancellable work somehow more consistently (pretty hacky)
* Fixed Crash when scrolling too much
* Added minDate/maxDate to the DateSelector
* Fixed accidental Garbage collection related error.
Merge pull request #18 from martinheidegger/master

Added new theme for NativeListDialog: IOS_PICKER_THEME that …