refactor(select): simplify the ngOptions regular expression

\w matches [a-zA-Z0-9_] and \d matches [0-9], using both in a character set is
simply redundant.

Closes #3903
feat(filter): allow map of filters to be registered

This feature adds similar functionality to what `$ControllerProvider.register`
and `$CompileProvider.directive` currently provide by allowing a map of filter
name/factories to be passed as the sole argument to `$FilterProvider.register`
to register all of the specified filters.

Closes #4036
Closes #4091
refactor($ngAnimate): simplify the animation event rewrite

To avoid code duplication, use single variables for keeping
properties/events names to use. Also, fix some errors that have
happened after the rewrite from moment ago.
chore($ngAnimate): simplify vendor prefixes handling in tests
fix(dateFilter): allow negative millisecond value strings
chore: remove Firefox CORS workaround

See #1468
fix($httpBackend): don't send empty string bodies

The `XMLHttpRequest.send` spec defines different semantics for `null`
than for an empty String: an empty String should be sent with a
`Content-Type` of `text/plain`, whereas `null` should have no
`Content-Type` header set.

Closes #2149
fix($animator): avoid completing the animation asynchronously unless CSS transtiions/animations are present

Closes #4023
Closes #3940
chore(grunt): switch to the new //# sourceMappingURL pragma

All browsers except from Chrome implemented both the old
"//@ sourceMappingURL" and the new "//# sourceMappingURL" pragmas
in the same version so the only reason to keep the old one was Chrome.
However, Chrome 29, i.e. current stable version already supports
the new pragma so there's no need to wait any longer.
fix($httpBackend): set headers with falsy values

This is a breaking change. To migrate to the new behavior,
delete or set headers to `undefined` to avoid having them sent.
To restore the old behavior, override `$httpBackendProvider`
with the old implementation.

Closes #2984
docs(ngRoute): add angularEvent param to $routeChangeStart event

Adds missing implied first argument, `angularEvent`, to match
the rest of the `$routeChange` event documentation.
fix($compile): allow interpolations for non-event handlers attrs

Fix wrong behaviour that didn't allow 'data-on' and 'on' element attributes
to be interpolated by $compile. The regex now accepts any string beginning
with 'on' and with at least one more English letter.
feat($compile): support tel: links in a[href]

Allow `tel:` links so that click-to-call works in mobile browsers
test($sce): make ie8 happy

Ref: https://github.com/angular/angular.js/pull/4221#/issuecomment-25515813

Closes #4221
style($qSpec): add semi-colons
style(rootScopeSpec): add semi-colons
fix($compile): ng-attr to support dash separated attribute names
docs($compile): improve explanation of Attributes.$observe

The current comment of Attributes.$observe doesn't state correctly the behavior when the attribute contains no interpolation. Specifically, it states that the observer function will never be invoked if the attribute contains no interpolation. However, the actual behavior in this case is that the observer will be invoked once during the next digest loop.
fix($scope): $evalAsync executes on the right scope

Executes $evalAsync at the scope that the call was made

Closes: #3548
test($sce): ie8 fix for entire file

Ref: https://github.com/angular/angular.js/pull/4221#/issuecomment-25515813

Closes #4221