Added form validation and css class for invalid timespans, #1494

src/css/less/grafana.less

@@ -13,6 +13,7 @@
 @import "gfbox.less";
 @import "dashlist.less";
 @import "admin.less";
+@import "validation.less";
 
 .row-control-inner {
   padding:0px;

src/css/less/validation.less

@@ -0,0 +1,3 @@
+input[type=text].ng-invalid {
+  box-shadow: inset 0 0px 7px @red;
+}