Two small UI changes: capacity -> capacity utilization, and the description for aggergated metrics (#3372)

diff --git a/heron/tools/ui/resources/static/js/plan-stats.js b/heron/tools/ui/resources/static/js/plan-stats.js
index 8b05861..d3607fb 100644
--- a/heron/tools/ui/resources/static/js/plan-stats.js
+++ b/heron/tools/ui/resources/static/js/plan-stats.js
@@ -33,11 +33,11 @@
     // Build the status table
     var rowData = [
       {
-        name: 'Capacity',
+        name: 'Capacity Utilization',
         metricName: 'capacity',
         get: getAndRenderStats,
         tooltip: 'Average tuple execute latency multiplied by number of tuples processed divided by the time period.',
-        legendDescription: 'capacity',
+        legendDescription: 'utilization of execution capacity',
         loMedHi: [0.1, 0.5, 1],
         scaleTicks: [0, 0.25, 0.5, 0.75, 1]
       },
diff --git a/heron/tools/ui/resources/templates/topology.html b/heron/tools/ui/resources/templates/topology.html
index 70dd003..3ad2816 100644
--- a/heron/tools/ui/resources/templates/topology.html
+++ b/heron/tools/ui/resources/templates/topology.html
@@ -67,7 +67,7 @@
               Click on a circle to color instances by their value for that metric."></span>
         </div>
         <p class="text-muted text-center">
-          <em>Click to color instances by metric over a time period</em>
+          <em>Click the circles below to color instances by metric over a time period</em>
         </p>
         <table class="stat-rollup-table">
           <tbody class="stats">