Bring back axis title

src/render.js

@@ -44,7 +44,7 @@ class Chart {
     }
 
     draw_yAxisTitle(title) {
-        const middle = (this.top - this.bottom) / 2.0
+        const middle = this.top + ((this.height) / 2.0)
         const x = 15
         this.canvas.append('text').attr('class', 'axis-title')
             .attr('text-anchor', 'middle').attr('dominant-baseline', 'middle')
@@ -335,9 +335,6 @@ export function render_clouds(canvas, width, height, offset, data) {
         .y(function(d) { return chart.yRange(d.coverage) })
         .curve(d3.curveBasis)
 
-    //chart.draw_xAxisLineTop()
-
-
     chart.set_yAxisTic(  0,   '0%')
     chart.set_yAxisTic( 50,  '50%')
     chart.draw_xGrid(   50, 'guide')