title: Using MEF to allow user to add custom plugins, to run a method and change a collection of datapoints
body: <p>I have an application that is built up with Prism and MEF.
  I have some modules (defined inside same solution) that I load in and everything works fine.</p>
  
  <p>However now I would like to allow the user to add their own plugins (basically these plugins should alter a collection of data points) - so in other words the user creates an algorithm(plugin) that changes these datapoints that are living inside a ViewModel.</p>
  
  <p>I need to define some kind of "Contract" that the user needs to ophold when creating a new plugin. How would I do this? </p>
  
  <p>The plugin should be a single .dll inside a /Plugin folder and should be loaded at runtime, a ListView should be populated in a view that contains a UserControl for each Plugin.</p>