Fix a bug where QuickDialogTableView would sometimes try to scroll to an indexPath beyond its bounds.

Removed QuickDialogTable::indexForElement: method because:

- it was only used in 2 places to obtain the NSIndexPath for the QElement to scroll to.
- it didn't take hidden QElements into account, which cause to NSRangeExceptions crashing an app

Instead, those 2 places now use QElement::getIndexPath which does take hidden QElements into account.
Use QElement::getIndexPath instead of QuickDialogTableView::visibleIndexForElement:

QuickDialogTableView::visibleIndexForElement: returns an incorrect
result after rows have been deleted dynamically from the tableview.

Since this method gives incorrect results and is only used in 1 place,
I deleted it and replaced it with QElement::getIndexPath which returns
the correct result.
- Fixed issue with QCountDownElement picker not showing proper value.
- Added example of QCountDownElement to "Date Time" section of usage examples.
Merge branch 'bug/fix_cellForElement_after_deleting_or_inserting_rows' into features/working_prevnext_buttons

Conflicts:
	quickdialog/QuickDialogTableView.m
When previous or next button tries to scroll to an offscreen cell, get the index path of the offscreen cell and not the currently selected cell.

This fixes a mistake made during merging.
Ensure that QEntryElements are deselected when pressing next or previous button.

This solves a bug where a QEntryElement with the keepSelected property set to YES would appear selected (selectedBackgroundView drawn) when recycled.
Many small bug fixes
Merged conflict
Reverted to the working segmentedelement. The code changes that were accepted never quite worked properly.
Added deselection to the QSelectSection element
Fixes bugs with segmented control and popovers
Minor fixes to appearance
Removed NSLogs
Redundant line
removed automatic require, it used deprecated cocoapods functions
Adds text alignment for buttons, and fixes bug with scrolling when there are hidden cells in screen.
UIDatePickerMode selection

Possibility to select the UIDatePickerMode from the method used to
initialize QDateInLineElement
Merge pull request #458 from mneorr/master

Removed automatic require from podspec
Merge pull request #459 from pepibumur/master

UIDatePickerMode selection
Fixes sample after merge broke API