Fixes typo regression as noted by @nicolasbadia.
Removes long deprecated properties of SC.TextFieldView: isPassword & continuouslyUpdatesValue. Starts standardizing to true/false.
Improves hint implementation of SC.TextFieldView. Previously, there were 3 ways to display the hint: via placeholder attribute, via a text overlay or via setting an initial value of the input field. The last way, setting the value of the input, is the oldest method and the least useful, because it requires a lot of extra work to modify the type of the input when it is a password field into a text field. This work is made even worse because Internet Explorer doesn't allow you to modify the type of the field and so the code gets quite ugly and has been the source of a lot of bugs.

But the second approach, using a text overlay, can do all of this with much simpler code and therefore we've removed the legacy approach for a two method approach: 1) use the placeholder when possible, unless hintOnFocus is true, or else 2) use a text overlay.
Fixes invalid unit test.
Adds warning for a possible cause of a failing unit test dependent on how the test was run.
Fixes up unit test and adds specific check for `hintOnFocus` being set to false.
Adds debug-mode only property validation to the layout property. Argument and property validation helps developers save time by failing at the root of the problem, providing useful messages and avoiding difficult to diagnose infinite loops. Normally, this type of validation would come at the expense of the performance of an application, but fortunately SproutCore's build tools allow us to separate all of this code entirely from production builds. Win-win!
Fixes an extremely rare security vulnerability in SC.TextFieldView that could occur if a hint overlay is used that included user generated hint. Also fixes @type of applyImmediately.
Removes an invalid condition that prevents key down validation in any browsers that support touch events (which has nothing to do with whether touch events will be used or not).