The example code for `$provide.value()` actually used `$provide.constant()`.
It now uses `$provide.value()`.

Closes #4983
Closes #4990

Closes #4420

This also contains some whitespace corrections by my editor.

This change makes `$injector.instantiate` (and thus `$provide.service`) to behave the same as native
`new` operator.

Improve the "tracking" service example by adding a configuration option.
Get better formatting of the generated code samples using <pre> tags.
Move the detailed explanations into each function's documentation block.
Improve the overview and list the constituent functions by significance.

Closes #4302

$provide's example seems awkward. Replace with more real-world example,
using an injected service, where the service defined has a good reason to
be a singleton.

There's quite a lot of confusion around $provide:
http://stackoverflow.com/search?q=angularjs+service+vs+factory
Tests for example at: http://jsbin.com/EMabAv/1/edit?js,output

Objects received from outside AngularJS may have had their `hasOwnProperty`
method overridden with something else. In cases where we can do this without
incurring a performance penalty we call directly on Object.prototype.hasOwnProperty
to ensure that we use the correct method.

Also, we have some internal hash objects, where the keys for the map are provided
from outside AngularJS. In such cases we either prevent `hasOwnProperty` from
being used as a key or provide some other way of preventing our objects from
having their `hasOwnProperty` overridden.

BREAKING CHANGE: Inputs with name equal to "hasOwnProperty" are not allowed inside
form or ngForm directives.

Before, inputs whose name was "hasOwnProperty" were quietly ignored and not added
to the scope.  Now a badname exception is thrown.

Using "hasOwnProperty" for an input name would be very unusual and bad practice.
Either do not include such an input in a `form` or `ngForm` directive or change
the name of the input.

Closes #3331