Get rid of dict.has_key(). Boy this has a lot of repercussions!

Not all code has been fixed yet; this is just a checkpoint...
The C API still has PyDict_HasKey() and _HasKeyString(); not sure
if I want to change those just yet.

Lib/asyncore.py

@@ -247,7 +247,7 @@ class dispatcher:
         fd = self._fileno
         if map is None:
             map = self._map
-        if map.has_key(fd):
+        if fd in map:
             #self.log_info('closing channel %d:%s' % (fd, self))
             del map[fd]
         self._fileno = None