MILC: Use dashes instead of underscores for subcommands

The subcommand functions' name follows the Python convention of using
snake case, but looks odd on the command line.
Fix it by converting underscores to dashes, eg.: list_keyboards ->
list-keyboards.

lib/python/milc.py

@@ -429,11 +429,12 @@ class MILC(object):
                 self.arg_only.append(arg_name)
                 del kwargs['arg_only']
 
+            name = handler.__name__.replace("_", "-")
             if handler is self._entrypoint:
                 self.add_argument(*args, **kwargs)
 
-            elif handler.__name__ in self.subcommands:
-                self.subcommands[handler.__name__].add_argument(*args, **kwargs)
+            elif name in self.subcommands:
+                self.subcommands[name].add_argument(*args, **kwargs)
 
             else:
                 raise RuntimeError('Decorated function is not entrypoint or subcommand!')
@@ -599,7 +600,7 @@ class MILC(object):
             self.add_subparsers()
 
         if not name:
-            name = handler.__name__
+            name = handler.__name__.replace("_", "-")
 
         self.acquire_lock()
         kwargs['help'] = description