Support named positional arguments

[electrum]

There should be a way to specify that exactly two arguments are required:

git remote add <name> <url>

Currently, this must be done as List<String>, which requires the user code to do the min/max checking, and doesn't allowing mixed types, such as String and URI.

[gaul]

Any suggestions on how to implement this?

[dain]

we could add something like:

  @Arguments
  void setArguments(String name, URI uri) {
    ...
  }

We can extract the names using paranamer (or the Java 8 apis).