Correct time formatting in RefreshTableHeaderView

Changed the time for RefreshTableHeaderView. In Australia in the
simulator it would display the time with a trailing "AM" or "PM", but
on the device it would only display "A" or "P". This fixes that and
preserves default date format.
Merge pull request #159 from ytn3rd/master

Correct displaying of time in update label.
Merge pull request #169 from cosmos21/master

Clear the text of the searchBar if the user taps the search's Cancel button.
Fixed GetImmediateRootElement when called on a Section. Previously it always returned null.

This caused issues with calling GetContainerTableView() on Sections.
Merge pull request #172 from Its-Tyson/section-getroot-issue

Section.GetImmediateRootElement() always returns null
Fixed a bug where DateTimeElements don't show any selection animation due to deriving from StringElement, and StringElements only enabling selection if the Tapped event is subscribed to. DateTime elements overload the OnSelected method and so never have a Tapped subscription. Fixed by forcing to always use a selection style.
Always use the same UITableViewCell, and resize the entry on demand.   Fixes #175
Merge pull request #173 from Its-Tyson/datetime-element-selection-issue

Fixed a bug where DateTimeElements don't show any selection animation.