TextFieldTextEditor: fixed issue on iOS where text would get immediately selected after entering a character, creating a situation where new text could not be entered without deselecting and reselecting. It was caused by textField.defaultTextFormat not properly comparing to a variable that should have been the same (closes #936)
TextFieldTextEditor: only calls validate() in selectRange() if it's not already validating
StageTextTextEditor: fixed issue on iOS with displayAsPassword where newly entered characters would immediately change to bullets, instead of after a delay (closes #881)
StageTextTextEditor: avoid calling selectRange() when the desired range is already selected to avoid showing the clipboard menu on iOS when multiline is true (closes #787)