Add checkId() for PyButton and PyInputBox, add id check for tags with pys- Event handlers (#400)

* Add id generation to PyButton and PyInputBox components

* Refactor init handlers and add check for id

pyscriptjs/src/components/pybutton.ts

@@ -37,6 +37,7 @@ export class PyButton extends BaseEvalElement {
     }
 
     connectedCallback() {
+        this.checkId();
         this.code = htmlDecode(this.innerHTML);
         this.mount_name = this.id.split('-').join('_');
         this.innerHTML = '';