Alternative adapt parse_date to handle ISO dates

Revert "Adapt parse_date to handle ISO dates"

This reverts commit bd0fce8,
and provides an alternative to ISO format.

babel/dates.py

@@ -1165,7 +1165,12 @@ def parse_date(string, locale=LC_TIME, format='medium'):
     if not numbers:
         raise ParseError("No numbers were found in input")
 
-    # TODO: try ISO format first?
+    # we try ISO format first YYYY-MM-DD
+    if len(numbers) == 3:
+        ints = list(map(int, numbers))
+        if ints[0] > 31 and ints[1] <= 12 and ints[2] <= 31:
+            return date(*ints)
+
     format_str = get_date_format(format=format, locale=locale).pattern.lower()
     year_idx = format_str.index('y')
     month_idx = format_str.index('m')
@@ -1181,19 +1186,12 @@ def parse_date(string, locale=LC_TIME, format='medium'):
     #        names, both in the requested locale, and english
 
     year = numbers[indexes['Y']]
-    day = numbers[indexes['D']]
-    month = numbers[indexes['M']]
     if len(year) == 2:
-        # check if we don't have an ISO kind of format
-        if len(day) == 4:  # day first locale
-            year, month, day = day, month, year
-        elif len(month) == 4:  # month first locale
-            year, month, day = month, day, year
-        else:
-            year = 2000 + int(year)
-    year = int(year)
-    month = int(month)
-    day = int(day)
+        year = 2000 + int(year)
+    else:
+        year = int(year)
+    month = int(numbers[indexes['M']])
+    day = int(numbers[indexes['D']])
     if month > 12:
         month, day = day, month
     return date(year, month, day)