支持SSR、升级Vue版本和增加新的icon (#40)

* search component add new style

* update vue version and support ssr

* unit test

* add new icon

* new icon

packages/picker/src/picker-column.vue

@@ -2,7 +2,8 @@
   <div class="van-picker-column" :class="classNames">
     <div class="van-picker-column-wrapper" :class="{ dragging: isDragging }" ref="wrapper" :style="{ height: visibleContentHeight + 'px' }">
       <div
-        v-for="item in currentValues"
+        v-for="(item, index) in currentValues"
+        :key="index"
         class="van-picker-column__item"
         :class="{ 'van-picker-column__item--selected': item === currentValue }"
         :style="{ height: itemHeight + 'px', lineHeight: itemHeight + 'px' }">

packages/picker/src/picker.vue

@@ -10,6 +10,7 @@
     <div class="van-picker__columns" :class="['van-picker__columns--' + columns.length]">
       <picker-column
         v-for="(item, index) in columns"
+        :key="index"
         v-model="values[index]"
         :values="item.values"
         :class-name="item.className"