[new feature] Stepper add plus & minus event (#294)

* [bugfix] CouponList always show empty info

* [bugfix] add click feedback of buttons in components

* [Doc] add custom theme document

* [new feature] Notice bar support more props

* [bugfix] PullRefresh test cases

* [bugfix] unused NoticeBar style

* [bugfix] Swipe width calc error

* [Doc] english document of all action components

* [Doc] change document site path to /zanui/vant

* [Doc] fix

* [bugfix] uploader style error

* [bugfix] tabs document demo

* [new feature] Cell support vue-router target route

* [bugfix] add cell test cases

* update yarn.lock

* [bugfix] Tabbar cann't display info when use icon slot

* [Doc] update document title

* [bugfix] Dialog should reset button text when showed

* [new feature] CouponList add showCloseButton prop

* [new feature] Swipe add 'initialSwipe' prop

* [bugfix] NoticeBar text disappeared when page back

* [new feature] ImagePreview support startPosition

* fix: improve imagePreview test cases

* [bugfix] Steps style error when has more than 4 items

* [new feature] normalize size of all icons

* [new feature] Stepper add plus & minus event

* fix: yarn.lock

* [bugfix] addressEdit icon render failed

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

@@ -7,7 +7,7 @@
 
 .van-icon {
   display: inline-block;
-  font: normal normal normal 14px/1 "vant-icon";
+  font: normal normal normal 14px/1 "<%= fontName %>";
   font-size: inherit;
   text-rendering: auto;
 

packages/vant-css/src/field.css

@@ -93,5 +93,9 @@
     top: 50%;
     transform: translate3d(0, -50%, 0);
     padding: 10px;
+
+    .van-icon {
+      display: block;
+    }
   }
 }