Add UNFORGIVING mode

* This will explicitly throw errors instead of handling them through
  Event Listeners

src/template/template-e6d.js

@@ -4,11 +4,18 @@ class TemplateE6d extends HTMLTemplateElement {
     this.preprocessed = false;
   }
 
+  connectedCallback() {
+    this.unforgiving = this.hasAttribute(`data-e6d-unforgiving`);
+  }
+
   dispatchError(type, detail) {
     const evtBroad = new CustomEvent(`e6d-error`, {detail,});
     const evtSpecific = new CustomEvent(`e6d-error-${ type }`, {detail,});
     this.dispatchEvent(evtBroad);
     this.dispatchEvent(evtSpecific);
+    if (this.unforgiving) {
+        throw new Error(`${ type }: ${ JSON.stringify(detail) }`);
+    }
   }
 
   preprocess() {
@@ -122,9 +129,6 @@ class TemplateE6d extends HTMLTemplateElement {
     this.preprocessed = true;
   }
 
-  connectedCallback() {
-  }
-
   bind(obj = {}) {
     this.preprocess();