Added interval options to panel

src/app/panels/histogram/module.html

@@ -54,7 +54,7 @@
       <input type="checkbox"  ng-model="panel.percentage" ng-checked="panel.percentage" ng-change="render()">
     </span>
     <span>
-      <label class="small">Interval</label> <select ng-change="set_interval(panel.interval);get_data();" class="input-small" ng-model="panel.interval" ng-options="interval_label(time) for time in _.union([panel.interval],['auto','1s','1m','5m','10m','30m','1h','3h','12h','1d','1w','1M','1y'])"></select>
+      <label class="small">Interval</label> <select ng-change="set_interval(panel.interval);get_data();" class="input-small" ng-model="panel.interval" ng-options="interval_label(time) for time in _.union([panel.interval],panel.intervals)"></select>
     </span>
   </form>
   <center><img ng-show='panel.loading && _.isUndefined(data)' src="img/load_big.gif"></center>

src/app/panels/histogram/module.js

@@ -84,6 +84,7 @@ function (angular, app, $, _, kbn, moment, timeSeries) {
       auto_int    : true,
       resolution  : 100,
       interval    : '5m',
+      intervals   : ['auto','1s','1m','5m','10m','30m','1h','3h','12h','1d','1w','1M','1y'],
       fill        : 0,
       linewidth   : 3,
       timezone    : 'browser', // browser, utc or a standard timezone