prevent autocomplete when doing bulk insertion (paste, drop text)

src/editor/parts.js

@@ -69,7 +69,7 @@ class BasePart {
 
     // inserts str at offset if all the characters in str were accepted, otherwise don't do anything
     // return whether the str was accepted or not.
-    insertAll(offset, str) {
+    validateAndInsert(offset, str) {
         for (let i = 0; i < str.length; ++i) {
             const chr = str.charAt(i);
             if (!this.acceptsInsertion(chr)) {
@@ -82,6 +82,16 @@ class BasePart {
         return true;
     }
 
+    insert(offset, str) {
+        if (this.canEdit) {
+            const beforeInsert = this._text.substr(0, offset);
+            const afterInsert = this._text.substr(offset);
+            this._text = beforeInsert + str + afterInsert;
+            return true;
+        }
+        return false;
+    }
+
     createAutoComplete() {}
 
     trim(len) {