feat(testability): add $$testability service

The $$testability service is a collection of methods for use when debugging
or by automated testing tools. It is available globally through the function
`angular.getTestability`.
For reference, see the Angular.Dart version at
https://github.com/angular/angular.dart/pull/1191
docs(filterFilter): add note on negation
fix($compile): use the correct namespace for transcluded svg elements

This fixes the case when a directive that uses `templateUrl`
is used inside of a transcluding directive like `ng-repeat`.

Fixes #8808
Closes #8816
feat($compile): bind isolate scope properties to controller

It is now possible to ask the $compiler's isolate scope property machinery to bind isolate
scope properties to a controller rather than scope itself. This feature requires the use of
controllerAs, so that the controller-bound properties may still be referenced from binding
expressions in views.

The current syntax is to prefix the scope name with a '@', like so:

    scope: {
        "myData": "=someData",
        "myString": "@someInterpolation",
        "myExpr": "&someExpr"
    },
    controllerAs: "someCtrl",
    bindtoController: true

The putting of properties within the context of the controller will only occur if
controllerAs is used for an isolate scope with the `bindToController` property of the
directive definition object set to `true`.

Closes #7635
Closes #7645
fix(ngBindHtml): throw error if interpolation is used in expression

Closes #8824
docs($filter): Date filter am/pm case

Use uppercase for AM/PM in date filter

fixes #8763
chore(compare-master-to-stable): make checks for bugfixes better

Prevent the script from alerting you if a docs fix has something like "Fixes typo in foo", which is
not how bugfixes are worded.

Closes #8801
fix(input): validate minlength/maxlength for non-string values

Use the viewValue rather than modelValue when validating. The viewValue should always be a string, and
should reflect what the user has entered, or the formatted model value.

BREAKING CHANGE:

Always uses the viewValue when validating minlength and maxlength.

Closes #7967
Closes #8811
fix(ngModel): always format the viewValue as a string for text, url and email types

NgModel will format all scope-based values to string when setting the viewValue for
the associated input element. The formatting, however, only applies to input elements
that contain a text, email, url or blank input type. In the event of a null or undefined
scope or model value, the viewValue will be set to null or undefined instead of being
converted to an empty string.
docs($q): fixed spelling, removed extra characters

Closes #8779
docs(FormController): document $submitted property

Closes #8732
docs($rootScope): remove duplicate `$digest()`

Closes #8840
perf(select): execute render after $digest cycle

This is an optimization to defer execution of the render function in the
select directive after the $digest cycle completes inside the
$watchCollection expressions.  This does a check to see if the render
function is already registered in the $$postDigestQueue before it passes
it into $$postDigest, guaranteeing that the DOM manipulation happens
only in one execution after the model settles.

Closes #8825
fix(currencyFilter): pass through null and undefined values

When these special values are passed through one-time binding will work correctly.

BREAKING CHANGE: previously the currency filter would convert null and undefined values into empty string, after this change
these values will be passed through.

Only cases when the currency filter is chained with another filter that doesn't expect null/undefined will be affected. This
should be very rare.

This change will not change the visual output of the filter because the interpolation will convert the null/undefined to
an empty string.

Closes #8605
fix(numberFilter): pass through null and undefined values

When these special values are passed through one-time binding will work correctly.

BREAKING CHANGE: previously the number filter would convert null and undefined values into empty string, after this change
these values will be passed through.

Only cases when the number filter is chained with another filter that doesn't expect null/undefined will be affected. This
should be very rare.

This change will not change the visual output of the filter because the interpolation will convert the null/undefined to
an empty string.

Closes #8605
Closes #8842
fix(ngSwitch): avoid removing DOM nodes twice within watch operation

Closes #8662
fix($animate): wait two until two digests are over until enabling animations

Even when no remote templates are to be downloaded, wait until the end of the
post digest queue before enabling animations since all $animate-triggered
animation events perform a post digest before running animations.

Closes #8844
fix(ngRepeat): improve errors for duplicate items

-Log the value that had the duplicate key, as well as the key
The error that is thrown when items have duplicate track by keys can be
confusing because only the duplicate key is logged.  If the user didn't
provide that key themselves, they may not know what it is or what item
it corresponds to.
refactor(locationSpec): make helper functions take an object

Makes tests more readable
fix($location): always resolve relative links in html5mode to `<base>` url

BREAKING CHANGE (since 1.2.0 and 1.3.0-beta.1):

Angular now requires a `<base>` tag when html5 mode of `$location` is enabled. Reasoning:
Using html5 mode without a `<base href="...">` tag makes relative links for images, links, ...
relative to the current url if the browser supports
the history API. However, if the browser does not support the history API Angular falls back to using the `#`,
and then all those relative links would be broken.

The `<base>` tag is also needed when a deep url is loaded from the server, e.g. `http://server/some/page/url`.
In that case, Angular needs to decide which part of the url is the base of the application, and which part
is path inside of the application.

To summarize: Now all relative links are always relative to the `<base>` tag.

Exception (also a breaking change):
Link tags whose `href` attribute starts with a `#` will only change the hash of the url, but nothing else
(e.g. `<a href="#someAnchor">`). This is to make it easy to scroll to anchors inside a document.

Related to #6162
Closes #8492

BREAKING CHANGE (since 1.2.17 and 1.3.0-beta.10):

In html5 mode without a `<base>` tag on older browser that don't support the history API
relative paths were adding up. E.g. clicking on `<a href="page1">` and then on `<a href="page2">`
would produce `$location.path()==='/page1/page2'. The code that introduced this behavior was removed
and Angular now also requires a `<base>` tag to be present when using html5 mode.

Closes #8172, #8233