Fixing the 'index 0' bug in features2adam

Fixes the bug where the error message "Argument with index 0 is used more than once" appears and prevents us from running features2adam from the command line.

Also, added a test for Features2ADAM, and updated PrintADAM (in support of the test) to use scala.Console.out rather than System.out, which appears to play better with the scala.Console.withOut method used in tests.