Add better fallback fonts in pcb rendering

Fixes #3

Author: qu1ck

InteractiveHtmlBom/ibom.html

@@ -225,7 +225,7 @@
   </style>
   <script type="text/javascript" >
     /*
-      Split.js - v1.3.5 
+      Split.js - v1.3.5
       MIT License
       https://github.com/nathancahill/Split.js
     */
@@ -507,7 +507,7 @@
       var ctx = canvas.getContext("2d");
       ctx.setTransform(1, 0, 0, 1, 0, 0);
       fontsize = 1.5 * scalefactor;
-      ctx.font = "bold " + fontsize + "px Monospace";
+      ctx.font = "bold " + fontsize + "px Consolas,\"DejaVu Sans Mono\",monospace";
       ctx.textBaseline = "middle";
       if (layer == "F") {
         ctx.translate(tx, ty);