perf(Scope): remove the need for the extra watch in $watchGroup

Instead of using a counter and an extra watch, just schedule the reaction function via $evalAsync.

This gives us the same/similar ordering and coalecsing of updates as counter without the extra
overhead. Also the code is easier to read.

Since interpolation uses watchGroup, this change additionally improves performance of interpolation.

In large table benchmark digest cost went down by 15-20% for interpolation.

Closes #8396
chore(Scope): remove deregisterNotifier feature for $watch

We no longer have a need for this feature that was added to primarily support
$watchGroup (see previous commit).

BREAKING CHANGE: deregisterNotifier callback for $watch is no longer available

This api was available only in the last few 1.3 beta versions and is not
very useful for applications, so we don't expect that anyone will be affected
by this change.
refact(select): don't recreate selectedSet on every digest loop

In the case of a "multiple" select, the model value is an array, changes
to which don't get picked up by NgModelController as it only looks for
object identity change.

We were rebuilding the `selectedSet` (a hash map of selected items) from
the modelValue on every turn of the digest. This is not needed as we can
simply use `$watchCollection` directly on the `$modelValue` instead.
fix($location) don't rewrite location when clicking on "javascript:" or "mailto:" link

Previously, absent a specified target attribute, when clicking on an anchor tag with an href beginning
with either "javascript:" or "mailto:", the framework would rewrite the URL, when it ought not to.

With this change, the browser is prevented from rewriting if the URL begins with a case-insensitive match
for "javascript:" or "mailto:", optionally preceeded by whitespace.

Closes #8407
Closes #8425
Closes #8426
docs(ngMockE2E): remove repeated word

Closes #8411
docs($http): add link to `$http.path()`

Closes #8424
docs(faq): remove the mention of IE8
docs(error/$injector/unpr): inadvertently redefining a module can cause error

Closes #8421
feat(jQuery): upgrade to jQuery to 2.1.1

The data jQuery method was re-implemented in 2.0 in a secure way. This made
current hacky Angular solution to move data between elements via changing the
value of the internal node[jQuery.expando] stop working. Instead, just copy the
data from the first element to the other one.

Testing cache leaks on jQuery 2.x is not possible in the same way as it's done
in jqLite or in jQuery 1.x as there is no publicly exposed data storage. One
way to test it would be to intercept all places where a jQuery object is created
to save a reference to the underlaying node but there is no single place in the
jQuery code through which all element creation passes (there are various
shortcuts for performance reasons). Instead we rely on jqLite.cache testing
to find potential data leaks.

BREAKING CHANGE: Angular no longer supports jQuery versions below 2.1.1.
docs(ngSubmit): add link to `form` docs to discourage double submission

Closes #6017