Community-Lab introduction

Modified script.txt from [d908ae5804] to [4fedc4f1ce].

   168    168      nodes, users, slices, slivers, etc.
   169    169   3. The researcher chooses a couple of nodes and creates sliver descriptions
   170    170      for them belonging to the previous slice.  Both sliver descriptions include
   171    171      a public interface to the CN and user-defined properties for telling apart
   172    172      the source sliver from the target one.  Sliver descriptions go to the
   173    173      registry.
   174    174   4. Each of the previous nodes gets a sliver description for it.  If enough
   175         -   resources are available, a container is created with the desired
   176         -   configuration.
          175  +   resources are available, a container is created by applying the desired
          176  +   configuration over the selected template.
   177    177   5. Once the researcher knows that slivers have been instantiated, the server
   178    178      can be commanded to activate the slice.  The server updates the registry.
   179    179   6. When nodes get instructions to activate slivers they start the containers.
   180    180   7. Containers run the experiment setup program and the run program.  The
   181    181      programs query sliver properties to decide their behaviour.
   182    182   8. Researchers interact straight with containers if needed (e.g. via SSH) and
   183    183      collect results from them.