docs(tutorial): fix grammar

Should either be "a different version" or "different versions";
this goes with the latter.

Closes #10249
docs(guide/ie): fixed minor typo

Closes #10251
fix(select): fix several issues when moving options between groups

* When an option was moved to a previous group, the group that
loose the option would remove the label from the controller
* When an entire option group was removed, the options in the
group were mot removed from the controller

Closes #10166
docs(ngHref): fix poor paragraph construction

It was bad.

In order to improve the docs, the inclusion of the last sentence would help define `ngHref` well.

Closes #10254
style(ngHref): make jscs happy ;-;
docs($rootElement): fix minor grammatical errors

Closes #10269
chore(docs): fix dangling links warning in $http API

Closes #10270
fix(Angular.js): toKeyValue is not serializing null values

Signed-off-by: Josh Kurz <jkurz25@gmail.com>
feat($anchorScroll): add support for scrolling independently of `$location.hash()`

Add an optional argument to `$anchorScroll()` to enable scrolling to an
anchor element different than that related to the current value of
`$location.hash()`. If the argument is omitted, the value of
`$location.hash()` will be used instead.

Closes #4568