Add layout and section support

Based on blade Templating system I had the support of layout / include / yield feature. 
calling a php function with the view_ prefix will do it's equivalent in blade. All Blade @ prefixed function are supported appart from stuff like test and loop (eg. @for, @foreach)

View
```haml

- view_extends("layout")

- view_section("content")
%p
Lorem ipsum dolor sit amet, consectetur adipiscing 
- view_stop()

```
Layout
```haml
%html
  %head
  %body
    %h1 Hi
    .content
      - view_yield("content")
```