Fix the check for overrides so it is able to handle the empty string

Closes #2575

Fix a check inside render for select elements with ngOptions, which
compares the selected property of an element with it's desired state.
Ensure the placeholder, if available, is explicitly selected if the model
value can not be found in the option list.
Without these fixes it's up to the browser implementation to decide which
option to choose. In most browsers, this has the effect of displaying the
first item in the list. In IE9 however, this causes the select to display
nothing.

Closes #2150, #1826

In IE the model is not updated when the input value is modified using the context
menu, e.g. pasting from the clipboard, or cutting all or part of the current value.
To capture these changes, we bind to the proprietary 'paste' and 'cut' events.

Closes #1462

If you wire up ngClass directly to an object on the scope, e.g. ng-class="myClasses",
where scope.myClasses = { 'classA': true, 'classB': false },
there was a bug that changing scope.myClasses.classA = false, was not being picked
up and classA was not being removed from the element's CSS classes.

This fix uses angular.equals for the comparison and ensures that oldVal is a copy of
(rather than a reference to) the newVal.

ngClassWatchAction, when called as a $watch function, gets the wrong old
value after it has been invoked previously due to observation of the
interpolated class attribute. As a result it doesn't remove classes
properly. Keeping track of the old value manually seems to fix this.

Closes #1637

The change to prevent <span> elements being wrapped around empty text nodes caused these empty text nodes to have scopes and controllers attached, through jqLite.data() calls, which led to memory leaks and errors in IE8.
Now we exclude all but document nodes and elements from having jqLite.data() set both in the compiler and in ng-view.

Fixes: #1968 and #1876

Apparently there is a really weird bug in IE6-8 that causes anchor textContent
to be reset with href content when both contain @ symbol.

Inserting a bogus comment node into all anchor elements in IE works around this
browser bug.

I'm fixing the issue via directive because that way we'll fix it for jQuery as
well.

I fixed an e2e test too because it was incorrect.

Closes #1949

The leak can occur when ngSwich is used inside ngRepeat or any other
directive which is destroyed while its transcluded content (which
includes ngSwitch) is not attached to the DOM.

Refactor ngSwitch to use controller instead of storing data on compile
node. This means that we don't need to clean up the jq data cache.
Controller reference is released when the linking fn is released.

Closes #1621

If the $last property is calculated from the original collectionLength
on an object and properties starting with $ were filtered out, then $last
is never applied and $middle is applied erroniously.

Closes #1789