utils.MainIf: rename 'getip' to 'poll'

+ change mechanism for getting hostname

display.py

@@ -234,7 +234,7 @@ class Display:
             self.send(SET_COLOR, 0, 0, 0, 11 + self.blink)  # yellow / blue
             self.text('.', 0, dotpos, dotpos+1)
             self.color()
-            self.text(mainif.hostname or self.hostname, 1)
+            self.text(mainif.hostname() or self.hostname, 1)
             # self.event.set()
             self.blink = not self.blink
         else:
@@ -242,7 +242,7 @@ class Display:
             self.show('(cancel)(reboot)(shdown)')
 
     def refresh(self):
-        mainif.getip()
+        mainif.poll()
         func = self.menu or self.net_display
         func(self.gettouch())