[Improvement] optimize staticClass (#337)

* fix: Tabbar icon line-height

* [new feature] progress add showPivot prop

* [new feature] TabItem support vue-router

* [new feature] update document header style

* [Doc] add toast english ducoment

* [bugfix] Search box-sizing wrong

* [Doc] update vant-demo respo

* [Doc] translate theme & demo pages

* [Doc] add Internationalization document

* [bugfix] remove unnecessary props

* [fix] optimize clickoutside

* [new feature] optimize find-parent

* [new feature]: change document title accordinng to language

* [new feature] Pagination code review

* [improvement] adjust icon-font unicode

* [improvement] Icon spinner color inherit

* [improvement] icon default width

* [bugfix] DateTimePicker validate date props

* [bugfix] Tab item text ellipsis

* [improvement] optimize single line ellipsis

* [Improvement] optimzie staticClass

packages/vant-css/scripts/icon-template.css

@@ -6,7 +6,6 @@
 }
 
 .van-icon {
-  width: 1em;
   display: inline-block;
   font: normal normal normal 14px/1 "<%= fontName %>";
   font-size: inherit;

packages/vant-css/src/icon.css

@@ -6,7 +6,6 @@
 }
 
 .van-icon {
-  width: 1em;
   display: inline-block;
   font: normal normal normal 14px/1 "vant-icon";
   font-size: inherit;

packages/vant-css/src/picker.css

@@ -20,12 +20,12 @@
   }
 
   &__cancel {
-    color: #3388FF;
+    color: $blue;
     float: left;
   }
 
   &__confirm {
-    color: #3388FF;
+    color: $blue;
     float: right;
   }
 

packages/vant-css/src/search.css

@@ -65,18 +65,15 @@
     transform: translateY(-50%);
     left: 10px;
     font-size: 16px;
-    line-height: 1;
   }
 
   .van-icon-clear {
     font-size: 14px;
-    line-height: 16px;
     position: absolute;
     right: 0;
     top: 50%;
     transform: translateY(-50%);
-    /* 增加 clear 点击区域 */
-    padding: 5px;
-    color: #888;
+    padding: 5px; /* increase click area */
+    color: $gray-dark;
   }
 }