Adding Main-Class statement inside MANIFEST.MF
Adding two new stackables: Num (for int/float) and Text (for Strings). Also, a class for dealing with the Stackable Stack and an exception (stack underflow)
Adding package 'robot': reimplementation of RVM (from Perl to Java) and 'Command' (for the triples 'label: comm arg')
Adding Main.java for tests (initially) and the game