Add __repr__ to BoutOptions

Not the best, because `eval(repr(f)) != f`, but more useful than
nothing

Author: ZedThree

src/boutdata/data.py

@@ -479,6 +479,9 @@ def format_inline_comment(name, options):
 
         return f.getvalue()
 
+    def __repr__(self):
+        return self.as_dict()
+
     def get_bool(self, name, default=None):
         """
         Convert an option value to a bool, in (almost) the same way as BOUT++.