fix #312 Update peg dependency?

Close #313
$onContentRefresh for custom attributes

Close #314
completing api docs

adding the missing paragraphs and some formatting
Prefixed the framework.

Impacted content is really the implementation, including:

- its code
- its documentation
- its tests

Here are the element which have been prefixed:

- `attributes` property of components' controllers
- `on<Attribute>Change` change handler of components' controllers
- `event` object available in environment of event handler expressions
- `scope` object available in environment of templates
Updated the playground regarding the prefixing of the API.

That includes:

- the playground runner
- the samples
	- code
	- documentation
Updated the prefixes for some missing elements.

Concerned elements are:

- the `elements` property of components definitions, to define what kind of content they can expect
- the associated `content` attribute on components instances referring to the instances of these elements
Fixed the prefixing of `content`.