Update webcam data management

configuration/config.toml.sample

@@ -1,5 +1,8 @@
 # Configuration file the LittlePrynter
 
+[defaults]
+signature = "Anonymous"
+
 # Printer settings
 [printer]
 vendor_id = "0x04b8"

src/static/js/webcam.js

@@ -193,7 +193,7 @@ function setup_events(){
     ev.preventDefault();
     try {
       await countDownToPicture();         // wait for countdown to finish
-      const data = await take_picture();  // take_picture can be async
+      var data = await take_picture();  // take_picture can be async
       print_picture(data);
     } catch (e) {
       alert("Failed to print a picture because : " + e);
@@ -212,6 +212,10 @@ function clear_canvas() {
 }
 
 function dataURLtoFile(dataurl, filename) {
+  if(dataurl === "") {
+    console.log("We didn't receive data");
+  }
+
   var arr = dataurl.split(','), mime = arr[0].match(/:(.*?);/)[1],
       bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
   while(n--){