Have past, future and recent return random dates

Functions `past` and `future` only returned dates EXACTLY N YEARS before
or after the reference date. Function `recent` only returned dates
EXACTLY N DAYS before the reference date.

For example, `faker.date.past(1)` would return either *Nov 12, 2014*, or
*Nov 12, 2013*, but nothing in-between.

Also, now you can call those functions without parameter, and N will
take the default value of `1`.

lib/date.js

@@ -4,18 +4,27 @@ var date = {
 
     past: function (years, refDate) {
         var date = (refDate) ? new Date(Date.parse(refDate)) : new Date();
+        var range = {
+          min: 1000,
+          max: (years || 1) * 365 * 24 * 3600 * 1000
+        };
 
         var past = date.getTime();
-        past -= faker.random.number(years) * 365 * 24 * 3600 * 1000; // some time from now to N years ago, in milliseconds
+        past -= faker.random.number(range); // some time from now to N years ago, in milliseconds
         date.setTime(past);
 
         return date;
     },
 
     future: function (years, refDate) {
         var date = (refDate) ? new Date(Date.parse(refDate)) : new Date();
+        var range = {
+          min: 1000,
+          max: (years || 1) * 365 * 24 * 3600 * 1000
+        };
+
         var future = date.getTime();
-        future += faker.random.number(years) * 365 * 3600 * 1000 + 1000; // some time from now to N years later, in milliseconds
+        future += faker.random.number(range); // some time from now to N years later, in milliseconds
         date.setTime(future);
 
         return date;
@@ -32,8 +41,13 @@ var date = {
 
     recent: function (days) {
         var date = new Date();
+        var range = {
+          min: 1000,
+          max: (days || 1) * 24 * 3600 * 1000
+        };
+
         var future = date.getTime();
-        future -= faker.random.number(days) * 24 * 60 * 60 * 1000; // some time from now to N days ago, in milliseconds
+        future -= faker.random.number(range); // some time from now to N days ago, in milliseconds
         date.setTime(future);
 
         return date;

test/date.unit.js

@@ -12,6 +12,14 @@ describe("date.js", function () {
             assert.ok(date < new Date());
         });
 
+        it("returns a past date when N = 0", function () {
+
+            var refDate = new Date();
+            var date = faker.date.past(0, refDate.toJSON());
+
+            assert.ok(date < refDate); // date should be before the date given
+        });
+
         it("returns a date N years before the date given", function () {
 
             var refDate = new Date(2120, 11, 9, 10, 0, 0, 0); // set the date beyond the usual calculation (to make sure this is working correctly)
@@ -36,7 +44,7 @@ describe("date.js", function () {
             var refDate = new Date();
             var date = faker.date.future(0, refDate.toJSON());
 
-            assert.ok(date > refDate); // date should be after the date given, but before the current time
+            assert.ok(date > refDate); // date should be after the date given
         });
 
         it("returns a date N years after the date given", function () {