Fixed: Ivars with accessors in a Category failed with duplicate ivar error
Fixed: Added test case
fix for missing textFieldBackgroundColor support
apply to contentView instead of bezelView
manual test
introduced cocoa methods for background color
changed test to use cocoa api
correction of typos
Fixed: Updated backgroundColor internal variable handling

Previously, _textFieldBackgroundColor was used as the internal variable, and getter/setter methods were explicitly declared to handle getting/setting this value.

This commit changes the name of the internal variable to match the Cocoa compliant method (backgroundColor/setBackgroundColor). It also declares an @accessor option to auto-generate the getter. The setter is explicitly declared because it needs to mark the object as needing display.

Additionally, the logic for the setting is moved from the older method, setTextFieldBackgroundColor, to the new one, setBackgroundColor, and a comment was made to clarify that the older one was deprecated with a link to this issue.
Fix: Remove _backgroundColor

This parameter exists on CPView, so it has been removed here. A note was added on the setter to identify that the parameter was defined in the superclass.
Fix: https://github.com/cappuccino/cappuccino/issues/2157

Possible bug in XMLHTTPRequest.  Thanks to hmsimmonds for locating the following:

http://connect.microsoft.com/IE/feedback/details/795580/ie11-xmlhttprequest-incorrectly-throws-invalidstateerror-when-setting-responsetype

https://github.com/enyo/dropzone/issues/179

In short, setting the "withCredentials" flag must be done after open().
removed collectionViewDidChangeSelection
Fixed: Methods viewDidMoveToSuperview viewDidMoveToWindow viewWillMoveToSuperview viewWillMoveToWindow not called as in Cocoa

Previously, when adding, removing, replacing a CPView, the framework didn't call the methods viewDidMoveToSuperview, viewDidMoveToWindow, viewWillMoveToSuperview and viewWillMoveToWindow as in Cocoa. Now it does.

The main change is that these methods will be called when removing a CPView.

Added unit-test in Tests/AppKit/CPViewTest.j
Fixed: memory leaks with CPNotifications

Previously, when removing a view, Cappuccino didn't clean the notification center. The notification center kept in reference old views.

This PR fix this issue. When a CPView is added to a view, the methods _removeObservers and _addObservers are called. In these both methods we remove and add the observer to the notification center if needed. _removeObservers and _addObservers are called for the view and its subviews. These both methods are called through the method viewWillMoveToSuperview.

When a CPView is removed, we only call the method _removeObservers.
When a CPWindow is closed, we call the method _removeObservers on its contentView.
When a CPWindow is about to be opened, we call the method _removeObservers and _addObservers on its contentView.

Refs #1880
Refs #2024

Test app in Tests/Manual/AttachedSheet2/SheetWindowController.j
Fixed: make sure to remove observers when opening a CPWindow
Fixed: revert commit abdf1156d4d3d33afff55e168881cd7729c28fe0 for CPComboBox
Fixed: added a boolean to avoid to addObservers seveal times
Fixed: added optimization for releasing observers
fixed unit test
Fixed: method viewWillMoveToWindow and viewDidMoveToWindow not called when when adding a view to a view without a window where the previous superview had a window