cleanup import statements and conform to PEP-8

Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/ui/Noninteractive.py

@@ -16,7 +16,8 @@
 #    along with this program; if not, write to the Free Software
 #    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 
-import sys, time
+import sys
+import time
 from UIBase import UIBase
 
 class Basic(UIBase):

offlineimap/ui/TTY.py

@@ -18,7 +18,7 @@
 
 from UIBase import UIBase
 from getpass import getpass
-import select, sys
+import sys
 from threading import *
 
 class TTYUI(UIBase):