图例支持单选，事件携带target

fix #239
fix #240

doc/doc.html

@@ -915,9 +915,9 @@ require(['echarts'], function(ec){
                             <td> 默认只设定了图例文字颜色（详见<a href="#TextStyle" title="">textStyle</a>） </td>
                         </tr>
                         <tr>
-                            <td> <b>{boolean}</b> selectedMode </td>
+                            <td> <b>{boolean | string}</b> selectedMode </td>
                             <td> true </td>
-                            <td> 选择模式，默认开启图例开关 </td>
+                            <td> 选择模式，默认开启图例开关，可选single，multiple </td>
                         </tr>
                         <tr>
                             <td> <b>{Object}</b> selected </td>
@@ -2126,7 +2126,7 @@ indicator : [
                             <td> 选中是扇区偏移量 </td>
                         </tr>
                         <tr>
-                            <td> <b>{string}</b> selectedMode </td>
+                            <td> <b>{boolean | string}</b> selectedMode </td>
                             <td> null </td>
                             <td> 饼图，地图 </td>
                             <td> 选中模式，默认关闭，可选single，multiple </td>

doc/example/map11.html

@@ -92,6 +92,7 @@ option = {
         orient: 'vertical',
         x:'left',
         data:['北京 Top10', '上海 Top10', '广州 Top10'],
+        selectedMode: 'single',
         selected:{
             '上海 Top10' : false,
             '广州 Top10' : false

src/component/legend.js

@@ -156,8 +156,8 @@ define(function (require) {
                         textFont: font,
                         textBaseline: 'top'
                     },
-                    hoverable : legendOption.selectedMode,
-                    clickable : legendOption.selectedMode
+                    hoverable : !!legendOption.selectedMode,
+                    clickable : !!legendOption.selectedMode
                 };
 
                 if (legendOption.orient == 'vertical'
@@ -503,11 +503,19 @@ define(function (require) {
 
         function _legendSelected(param) {
             var itemName = param.target._name;
+            if (legendOption.selectedMode === 'single') {
+                for (var k in _selectedMap) {
+                    _selectedMap[k] = false;
+                }
+            }
             _selectedMap[itemName] = !_selectedMap[itemName];
             messageCenter.dispatch(
                 ecConfig.EVENT.LEGEND_SELECTED,
                 param.event,
-                {selected : _selectedMap}
+                {
+                    selected : _selectedMap,
+                    target : itemName
+                }
             );
         }