Increased size of the benchmark charts; disabled the chart display while the chart is being generated

assets/scripts/reports.coffee

@@ -9,6 +9,7 @@ $ ->
     a.click()
 
   $('#reports-button').on 'click', (e) ->
+    $('#reports-download').attr('disabled', true)
     chartInstance.destroy() if chartInstance
 
     benchmarkId = $('#report-benchmarks').val()
@@ -78,3 +79,4 @@ $ ->
       plugins: [ChartDataLabels]
 
     $('#reports-download').attr('disabled', false)
+    $('#benchmark-chart')[0].removeClass('disabled')