docs(tutorial): add missing semicolon to code snippet

Lets encourage people to use semicolons in javascript :>

Closes #5834
docs(contributing): add instructions to install grunt-cli/bower globally on unix systems

Closes #5814
Closes #5811
docs(ngChange): clarify difference between ng-change DOM change event

The ng-change event triggers immediately, which makes a difference for text input fields and text
areas, where the JavaScript onchange event would only be called at the end of the change.

Closes #5640
docs($sce): correct documentation for angular 1.2.0

Include mention of `ngSanitize` (and add it to the example), as well as removing (and clarifying if
needed) references to `ng-html-bind-unsafe`.

Closes #5551
docs(input): document ngValue directive

Extend the example with ng-value showing how to deal with default checked radio boxes.

Closes #5654
docs(api): adds links to top level guides

The main api docs page is probably the main landing page for many devs
looking to learn angular, so linking to the main guide pages would
likely help.

Closes #5869
docs(directive): link to directive registration api function

Originally, this issue was regarding documenting `restrict: 'CM'` in the directive guide, but it
was pointed out that the restrict documentation is covered in the $compile documentation. Because of
this, a link was simply added to the $compile documentation.

However, the wording suggests that it's actually linking to the directive registration function, in
$compileProvider, so the docs will link there instead. There is a link only a paragraph below to the
$compile documentation, so this does not hurt.

Closes #5516