Remove a lot of unused imports

Signed-off-by: Daniel Narvaez <dwnarvaez@gmail.com>

examples/alert.py

@@ -1,6 +1,6 @@
 from gi.repository import Gtk
 
-from sugar3.graphics.alert import Alert, TimeoutAlert
+from sugar3.graphics.alert import TimeoutAlert
 
 def _destroy_cb(widget, data=None):
     Gtk.main_quit()

examples/radiopalette.py

@@ -3,8 +3,6 @@ from gi.repository import Gtk
 from sugar3.graphics.radiopalette import RadioPalette, RadioMenuButton, \
                                         RadioToolsButton
 from sugar3.graphics.radiotoolbutton import RadioToolButton
-from sugar3.graphics.toolbutton import ToolButton
-from sugar3.graphics import style
 
 window = Gtk.Window()
 

examples/toolbar.py

@@ -2,7 +2,6 @@ from gi.repository import Gtk
 
 from sugar3.graphics.toolbutton import ToolButton
 from sugar3.graphics.toolbarbox import ToolbarBox, ToolbarButton
-from sugar3.graphics import style
 
 window = Gtk.Window()