Support for Async Task in Server calls

[OnurGumus]

NemerleWeb supports server calls as below:

public class Server
    {
      public GetNames() : List[string]
      {
        Helpers.GetNames().ToList();
      }
    }

But async task calls should be supported, since they will improve performance when I/O is involved:

    public class Server
    {
      public async GetNames() :Task[ List[string]]
      {
          await Helpers.GetNames().ToListAsync();
      }
    }

Nemerle supports this feature via async macro:

https://sites.google.com/site/gibekm/programming/nemerle/asyncawait

Nemerle.Async.dll from installer.