sort choices to make it easier to select

The sorting is applied to both standard and GMT choices.

timezone_field/choices.py

@@ -14,7 +14,7 @@ def standard(timezones):
     for tz in timezones:
         tz_str = str(tz)
         choices.append((tz, tz_str.replace("_", " ")))
-    return choices
+    return sorted(choices, key=lambda tup: tup[1])
 
 
 def with_gmt_offset(timezones, now=None, use_pytz=None):
@@ -41,4 +41,4 @@ def with_gmt_offset(timezones, now=None, use_pytz=None):
         _choices.append((delta, tz, display))
     _choices.sort(key=lambda x: x[0])
     choices = [(one, two) for zero, one, two in _choices]
-    return choices
+    return sorted(choices, key=lambda tup: tup[1])