Fix SVG to W3C standards

src/dgenies/static/js/d3.boxplot.js

@@ -262,8 +262,6 @@ d3.boxplot.draw_left_axis = function (y_max, y_min = 0) {
         .attr("preserveAspectRatio", "none");
 
     let container_left = svg_left.append("g")
-        .attr("width", axis_length)
-        .attr("height", 20)
         .attr("transform", "translate(0," + axis_length + ")rotate(-90)");
 
     let y_size = y_max - y_min;
@@ -491,8 +489,6 @@ d3.boxplot.draw_right_axis = function (y_zones=d3.boxplot.y_zones) {
         .attr("preserveAspectRatio", "none");
 
     let container_right = svg_right.append("g")
-        .attr("width", axis_length)
-        .attr("height", 20)
         .attr("transform", "translate(20)rotate(90)");
 
     container_right.append("text")

src/dgenies/static/js/dgenies.result.export.js

@@ -32,7 +32,10 @@ dgenies.result.export.export_svg = function () {
     window.setTimeout(() => {
         let transform = d3.boxplot.container.attr("transform");
         let after = function () {
-            let blob = new Blob([dgenies.result.export.get_svg()], {type: "image/svg+xml"});
+            let svg = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" " +
+                      "\"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\">";
+            svg += dgenies.result.export.get_svg();
+            let blob = new Blob([svg], {type: "image/svg+xml"});
             d3.boxplot.zoom.restore_scale(transform);
             dgenies.result.export.save_file(blob, "svg");
         };