fix millisecs versus microsecs

changed ago.py
changed setup.py
changed test_ago.py

ago.py

@@ -3,7 +3,7 @@ from datetime import (
   timedelta,
 )
 
-units = ('year', 'day', 'hour', 'minute', 'second', 'microsecond')
+units = ('year', 'day', 'hour', 'minute', 'second', 'millisecond', 'microsecond')
 
 def get_delta_from_subject(subject):
     subject_type = type(subject)
@@ -28,7 +28,8 @@ def delta2dict(delta):
         'hour'   : int(delta.seconds / 3600),
         'minute' : int(delta.seconds / 60) % 60,
         'second' : delta.seconds % 60,
-        'microsecond' : delta.microseconds
+        'millisecond' : delta.microseconds/1000,
+        'microsecond' : delta.microseconds%1000,
     }
 
 def human(subject, precision=2, past_tense='{} ago', future_tense='in {}', abbreviate=False):
@@ -56,7 +57,12 @@ def human(subject, precision=2, past_tense='{} ago', future_tense='in {}', abbre
         if count >= precision: break # met precision
         if d[ unit ] == 0: continue # skip 0's
         if abbreviate:
-            abr = 'mu' if unit == 'microsecond' else unit[0]
+            if unit == 'millisecond':
+                abr = 'ms'
+            elif unit == 'microsecond':
+                abr = 'um'
+            else:
+                abr = unit[0]
             hlist.append('{}{}'.format(d[unit], abr))
         else:
             s = '' if d[ unit ] == 1 else 's' # handle plurals