renderFromHTML API method (#654)

* renderFromHTML API method

* Fix case when currentBlock is undefined

* Clear editor before render

* Handle single block processing

* Update paragraph

types/api/blocks.d.ts

@@ -16,6 +16,13 @@ export interface Blocks {
    */
   render(data: OutputData): Promise<void>;
 
+  /**
+   * Render passed HTML string
+   * @param {string} data
+   * @return {Promise<void>}
+   */
+  renderFromHTML(data: string): Promise<void>;
+
   /**
    * Removes current Block
    */