docs(guide/migrate): add breaking changes for 1.3

See #8072
chore($parse): remove simpleGetter optimizations as they're no longer valid

Closes #8101
docs(ngInclude): remove @eventOf jsdocs tag

The @eventOf tag was causing a warning on build. I removed the tag and changed the @name to match
the previous comment blocks.

Closes #8140
docs(CHANGELOG): add v1.3.0-beta.15 and v1.2.20 changes
docs($parse:isecdom): add a section about return values and CoffeeScript

Closes #7973
docs($http): remove invalid JSDOC tags for patch() method

The @methodOf tag was causing a warning on build. I removed the tag and changed the @name to match
the previous comment blocks.

Closes #8170
docs(ngAnimate): ensure the CSS breakdown example uses a compound selector
feat(ngTransclude): allow ngTransclude to be used as an element

Closes #8141
fix($rootScope): remove support for a watch action to be a string

BREAKING CHANGE:

Previously, it was possible for an action passed to $watch
to be a string, interpreted as an angular expresison. This is no longer supported.
The action now has to be a function.
Passing an action to $watch is still optional.

Before:

```js
$scope.$watch('state', ' name="" ');
```

After:

```js
$scope.$watch('state', function () {
  $scope.name = "";
});
```

Closes #8190
fix(csp): fix autodetection of CSP + better docs

CSP spec got changed and it is no longer possible to autodetect if a policy is
active without triggering a CSP error:

https://github.com/w3c/webappsec/commit/18882953ce2d8afca25f685557fef0e0471b2c9a

Now we use `new Function('')` to detect if CSP is on. To prevent error from this
detection to show up in console developers have to use the ngCsp directive.

(This problem became more severe after our recent removal of `simpleGetterFn`
 which made us depend on function constructor for all expressions.)

Closes #8162
Closes #8191
test(jqLite): increase timeout and add a label

This test has been flaky on Sauce+IE.
I think 2secs might be not enough for IE sometimes.
chore(travis): enable SL video recording
chore(travis): increase browserNoActivityTimeout

We’ve seen many failures recently because of Karma killing a browser
after browserNoActivityTimeout. It’s possible that this is not any issue
other than super slow network / proxy.

Will try higher timeout and observe for a while.
docs(guide/unit-testing): add info on testing element transclude directives

Closes #4505
Closes #8197
refactor($compile): improve readability on conditional assignment

Use ternary operator instead of if statement

Closes #5065
refactor(dateFilter): improve readability on conditional assignment

Use ternary operator instead of if statement

Closes #5065
refactor($http): improve readability on conditional assignment

Use ternary operator instead of if statement

Closes #5065
refactor($parse): improve readability on conditional assignment

Use logical OR operator instead of if statement

Closes #5065
fix(ngRoute): remove unnecessary call to decodeURIComponent

Since `$location.$$path` is already decoded, doing an extra `decodeURIComponent` is both unnecessary
and can cause problems. Specifically, if the path originally includes an encoded `%` (aka `%25`),
then ngRoute will throw "URIError: URI malformed".

Closes #6326
Closes #6327
fix(orderBy): correctly order by date values

Closes #6675
Closes #6746