allow for negative years in dates

lib/OpenLayers/BaseTypes/Date.js

@@ -91,7 +91,7 @@ OpenLayers.Date = {
      */
     parse: function(str) {
         var date;
-        var match = str.match(/^(?:(\d{4})(?:-(\d{2})(?:-(\d{2}))?)?)?(?:(?:T(\d{1,2}):(\d{2}):(\d{2}(?:\.\d+)?)(Z|(?:[+-]\d{1,2}(?::(\d{2}))?)))|Z)?$/);
+        var match = str.match(/^(?:(-?\d{4})(?:-(\d{2})(?:-(\d{2}))?)?)?(?:(?:T(\d{1,2}):(\d{2}):(\d{2}(?:\.\d+)?)(Z|(?:[+-]\d{1,2}(?::(\d{2}))?)))|Z)?$/);
         if (match && (match[1] || match[7])) { // must have at least year or time
             var year = parseInt(match[1], 10) || 0;
             var month = (parseInt(match[2], 10) - 1) || 0;

tests/BaseTypes/Date.html

@@ -35,7 +35,7 @@
     
     function test_Date_parse(t) {
         
-        t.plan(114);
+        t.plan(121);
         
         var cases = {
             "2000": {
@@ -139,6 +139,11 @@
                 year: 2000,
                 month: 3,
                 date: 15
+            },
+            "-0501-03-01T00:00:00.000Z": {
+                year: -501,
+                month: 2,
+                date: 1
             }
         };