Added getmtime() function for use by ".pyc" processing.

(Similar to Emacs ".elc" files.)

function on creation.  (There's a funny thing about the return
value of the close function that should be resolved.)
Also added 'isatty' method.

must (pretend to) support all operations except assignments;
if you don't want to support an operation you have to provide
a dummy function that raises an exception...

Added _exit, exec, fork, getpid, getppid, kill and wait.

Don't report WE_MENU events with None as menu pointer;
Added stdwin.getactie() function;
Moved code to turn WINDOW* into windowobject* to a separate function.

Implement long_pow.

Moved some functions around.