calling self.tk.getint() and self.tk.getdouble(), call the globals
getint() and getdouble(), which in turn are just names for the Python
builtins int() and double().  (Making them globals actually save a
dict lookup compared to using the built-in.)  The corresponding
methods of class Misc have been changed similarly.  (Note that
getboolean() hasn't been changed because there's no Python
equivalent.)

The use of int() and float() has another advantage: if/when Tcl calls
can actually return Tcl objects with other types than string, use of
int() and float() is essential.