anchor.diff:  
   == Quick reference
   
  -Basic usage is a block _takeScreenshot_ that points to a URL:
  -The content of the block is used as the caption of the image.
  +Basic usage is a block macro _takeScreenshot_ that points to a URL:
  +The title of the block macro is used as the caption of the image.
   
   ```
  -[takeScreenshot, url=http://google.com, name=google]
  -Google Landing page
  +.Google Landing page
  +takeScreenshot::http://google.com[google]
   ```
   
   Use a block _driveBrowser_ to control the browser (i.e. for filling in a form or doing a login)
  
positive.code: ```
  
  ```
  [takeScreenshot, frame=BROWSER]
  Some propositions should appear
  ```
  
  ```
  [driveBrowser, dimension=IPHONE5]
    $("h3.r a").click()
  ```
  
  ```
  [takeScreenshot, frame=NEXUS5]
  Look Ma, it's Nexus 5!
  ```
  
negative.code: 
  === takeScreenshot
  
  The _takeScreenshot_ block macro has the syntax `takeScreenshot::<url>[<parameters>]` and supports the following parameters
  (note: the URL is not needed when the browser was navigated to the page using a _driveBrowser_ block or other means)
  
  name:: an optional unique file name (will be generated otherwise), the screenshot will be called `<name>.png`. This is the first positional parameter.
  frame:: Try awesomeness with `iphone5`, `nexus5` or `browser`. This is the second positional parameter.
  dimension:: size of the screenshot in the format `<width>x<height>` for instance 800x600. Also the values of 'frame' are supported.
  selector:: the CSS-like dom selector to screenshot. Only this will be part of the image. For instance `div #login_window`.
  
  Note: it is not allowed to set both 'frame' and 'dimension' or 'frame' and 'selector' for a screenshot.
  Note: `takeScreenshot::http://google.com[google]` and `takeScreenshot::http://google.com[name=google]` are equivalent.
  
  === driveBrowser
  
  The _driveBrowser_ block supports the following parameters:
  
  dimension:: size of the screenshot in the format `<width>x<height>` for instance 800x600. Also the values of 'frame' are supported. This is the first positional parameter.
  
  == Examples
  
  ```
  .The Google landing page
  takeScreenshot::http://google.com[google]
  ```
  
  ```
  