Special case 'entrySet' on Map fetcher.

You can't normally reflectively access methods on Map because it has a
special fetcher, but being able to reflectively access 'entrySet' is
super useful when you want to iterate over the keys+values of a map, so
we're going to hack it in there. Ha!

src/main/java/com/samskivert/mustache/BasicCollector.java

@@ -71,7 +71,10 @@ public abstract class BasicCollector implements Mustache.Collector
     protected static final Mustache.VariableFetcher MAP_FETCHER = new Mustache.VariableFetcher() {
         public Object get (Object ctx, String name) throws Exception {
             Map<?,?> map = (Map<?,?>)ctx;
-            return map.containsKey(name) ? map.get(name) : Template.NO_FETCHER_FOUND;
+            if (map.containsKey(name)) return map.get(name);
+            // special case to allow map entry set to be iterated over
+            if (name == "entrySet") return map.entrySet();
+            return Template.NO_FETCHER_FOUND;
         }
         @Override public String toString () {
             return "MAP_FETCHER";

src/test/java/com/samskivert/mustache/SharedTests.java

@@ -70,6 +70,14 @@ public abstract class SharedTests extends GWTTestCase
             "foo", Arrays.asList(context("bar", "baz"), context("bar", "bif"))));
     }
 
+    @Test public void testMapEntriesSection () {
+        Map<String,String> data = new HashMap<String,String>();
+        data.put("k1", "v1");
+        data.put("k2", "v2");
+        test("k1v1k2v2", "{{#map.entrySet}}{{key}}{{value}}{{/map.entrySet}}",
+             context("map", data));
+    }
+
     @Test public void testArraySection () {
         test("bazbif", "{{#foo}}{{bar}}{{/foo}}",
              context("foo", new Object[] { context("bar", "baz"), context("bar", "bif") }));