cell.userInteractionEnabled is now equal to the enabled property of the Element it belongs to.

This fixes a bug that still allowed you to select cells whose Elements had been disabled dynamically.

e.g.:  Let's say we have 2 QPickerElements. The second QPickerElement changes it's options based on the value of the first. If the first QPickerElement value is empty, then the second QPickerElement should have no values, and should be disabled.

With this fix, you can set secondQPickerElement.enabled = NO and then use UITableView's reloadRowsAtIndexPaths:withRowAnimation to properly disable it in the UITableView.

This was not possible before, because the userInteractionEnabled property was only set correctly in the implementation of QButtonElement and QElement, which wasn't always reached because not all QElement subclasses call super (e.g. QPickerElement)
Merge pull request #464 from bartvandendriessche/features/cells_respect_element_enabled_property

Make cells user interaction respect their element's enabled property
Deselect row when navigation controller pop

Before this change when the view pop back the cell didn't deselect
automatically
Rev'd up podspec
Forget to change it here. Sorry.
Merge pull request #474 from russ/master

Rev'd up podspec
Merge pull request #470 from pepibumur/master

Deselect QMultiLineElement when back