Fixes a number of issues with SC.SplitView:

- Adds layoutDirection property and class-name to SplitDividerView. Hooks up propagation from parent SplitView.
- Fixes bug where SplitView's class-names would update incorrectly when layoutDirection changed. (Previous class was not being removed.)
- Fixes CSS bug where selector hierarchies were insufficiently specific, causing a misapplication of styles in nested SplitViews with different layoutDirections.
- Includes unit tests.
Revert "Swaps out @jlaxson's SC.SegmentedView#shouldAutoResize for @publickeating's suggestion that the behavior be mediated by setting shouldHandleOverflow to NO. (There is currently no way to prevent resizing in a static-width segmented view with shouldHandleOverflow: NO; if that's a need, it shouldn't be hard to implement.)"

This reverts commit 3f9128971e9ce7da0b97221a3dbd71975a90fb7c.
Updates README with some better links and new verbiage.
Adds an escapeForCSS method to SC.String.

The '.' and ':' characters are valid in HTML ids, but cannot be used in
a jQuery selector without being escaped. I added a method to escape a
string for use as a jQuery selector.
Renames `escapeForCss` to the less-nice but more-precise `escapeCssIdForSelector`.
Tiny bit of whitespace clean up.
Removes forcing the prototype layout onto all child views which is redundant and prevents child views from having their own layout.
Prevents SC.CollectionView from pooling views that don't have a layout (i.e. static views). Fixes failing unit test.
JSHint cleanup.
Adds unit tests verifying the reset of an SC.Store.
Fixes bug that doesn't clear nested records from a store reset (fixes failing unit test in previous commit).
Fixes the debug only SC.PickerPane message. This helps developers avoid confusion if accidentally calling append instead of popup on a picker pane.
Fixes circular dependency between view/animation and view/layout_style.
Adds tests showing problems working with SC.ChildArray items. Adds test for deep property (more than one level nested) updates.
Tidies nested record unit tests.
Adds tests highlighting the intricacies of how nested records change depending on when and how they're accessed.
Tidies up SC.ChildrenAttribute and removes the call override which doesn't appear to add any value.
Small cleanup of unit test.
Refactors SC.ChildArray to:
 - remove range observers on the underlying data hash array
 - tackle the difficult issue of separating removed nested records from the array and the parent record (fixes failing unit tests)
 - optimizes SC.ChildArray to not be as noisy
 - clean up a bunch of incorrect documentation copied and pasted over from SC.ManyArray
 - hopefully, makes the code more understandable and easy-to-follow
Adds debug-mode only toString method for SC.ChildArray to give a bit more information akin to SC.ManyArray & SC.RecordArray.