Support browser dist without canvas dependency

In a non-node environment, none of jsdom, xmldom, or canvas packages
are required, instead browser primitives are used. Make the handling
of these three requirements consistent, omit them from the browser
build, and mark dependencies peer plus dev rather than direct.

Update dist files, and package lock to latest minor versions.

dist/browser/canvg.js

@@ -9,14 +9,13 @@
  */
 
 (function (global, factory) {
-	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory(require('rgbcolor'), require('stackblur-canvas'), require('canvas')) :
-	typeof define === 'function' && define.amd ? define(['rgbcolor', 'stackblur-canvas', 'canvas'], factory) :
-	(global.canvg = factory(global.RGBColor,global.StackBlur,global.Canvas));
-}(this, (function (rgbcolor,stackblurCanvas,canvas) { 'use strict';
+	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory(require('rgbcolor'), require('stackblur-canvas')) :
+	typeof define === 'function' && define.amd ? define(['rgbcolor', 'stackblur-canvas'], factory) :
+	(global.canvg = factory(global.RGBColor,global.StackBlur));
+}(this, (function (rgbcolor,stackblurCanvas) { 'use strict';
 
 	rgbcolor = rgbcolor && rgbcolor.hasOwnProperty('default') ? rgbcolor['default'] : rgbcolor;
 	stackblurCanvas = stackblurCanvas && stackblurCanvas.hasOwnProperty('default') ? stackblurCanvas['default'] : stackblurCanvas;
-	canvas = canvas && canvas.hasOwnProperty('default') ? canvas['default'] : canvas;
 
 	function createCommonjsModule(fn, module) {
 		return module = { exports: {} }, fn(module, module.exports), module.exports;

dist/node/canvg.js

@@ -11,7 +11,7 @@
 (function (global, factory) {
 	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory(require('rgbcolor'), require('stackblur-canvas'), require('canvas'), require('jsdom'), require('xmldom')) :
 	typeof define === 'function' && define.amd ? define(['rgbcolor', 'stackblur-canvas', 'canvas', 'jsdom', 'xmldom'], factory) :
-	(global.canvg = factory(global.RGBColor,global.StackBlur,global.Canvas,global.jsdom,global.xmldom));
+	(global.canvg = factory(global.RGBColor,global.StackBlur,global.canvas,global.jsdom,global.xmldom));
 }(this, (function (rgbcolor,stackblurCanvas,canvas,jsdom,xmldom) { 'use strict';
 
 	rgbcolor = rgbcolor && rgbcolor.hasOwnProperty('default') ? rgbcolor['default'] : rgbcolor;
@@ -32,9 +32,10 @@
 
 	var isNode = (module.exports && typeof window === 'undefined'),
 	  nodeEnv = true;
-	var JSDOM, windowEnv;
+	var Canvas, JSDOM, windowEnv;
 
 	{
+	  Canvas = canvas;
 	  JSDOM = jsdom.JSDOM;
 	  windowEnv = new JSDOM().window;
 	  windowEnv.DOMParser = xmldom.DOMParser;
@@ -47,7 +48,7 @@
 	function createCanvas(width, height) {
 	  var c;
 	  {
-	    c = canvas.createCanvas(width, height);
+	    c = Canvas.createCanvas(width, height);
 	  }
 	  return c;
 	}
@@ -3312,7 +3313,7 @@
 	    svg.Images.push(this);
 	    this.loaded = false;
 	    if (!isSvg) {
-	      this.img = new canvas.Image();
+	      this.img = new Canvas.Image();
 	      if (svg.opts['useCORS'] == true) { this.img.crossOrigin = 'Anonymous'; }
 	      var self = this;
 	      this.img.onload = function () { self.loaded = true; };