Remove arguments from verbosity flag

'-v' and '--verbose' no longer accept an argument, optional or
otherwise. Instead, they simply act as a flag.

This dramatically simplifies the help text and implementation of the
flags.

Bone Market Solver.py

@@ -2458,10 +2458,8 @@ def main():
 
     parser.add_argument(
             "-v", "--verbose",
-            nargs='?',
-            const=True,
+            action='store_true',
             default=False,
-            type=bool,
             help="whether the solver should output search progress rather than showing intermediate solutions",
             dest='verbose'
             )