improve blockly linting

Author: ThomasPohl

admin/blockly.js

@@ -1,9 +1,9 @@
 'use strict';
 
-var goog = goog || undefined;
-var Blockly = Blockly || undefined;
-var main = main || undefined;
-var document = document || undefined;
+/*global goog:true */
+/*global Blockly:true */
+/*global main:true */
+/*global document:true */
 
 if (typeof goog !== 'undefined') {
     goog.provide('Blockly.JavaScript.Sendto');

admin/blocks/append.js

@@ -1,6 +1,6 @@
 'use strict';
-var Blockly = Blockly || undefined;
-var getInstances = getInstances || undefined;
+/*global Blockly:true */
+/*global getInstances:true */
 
 /// --- Append  --------------------------------------------------
 Blockly.Words['google-spreadsheet_append_add-to'] = { en: 'append to', de: 'füge zu' };

admin/blocks/createSheet.js

@@ -1,6 +1,6 @@
 'use strict';
-var Blockly = Blockly || undefined;
-var getInstances = getInstances || undefined;
+/*global Blockly:true */
+/*global getInstances:true */
 
 /// ---Create sheet  --------------------------------------------------
 Blockly.Words['google-spreadsheet_create-sheet_create-in'] = { en: 'create in', de: 'erstelle in' };

admin/blocks/deleteRows.js

@@ -1,6 +1,6 @@
 'use strict';
-var Blockly = Blockly || undefined;
-var getInstances = getInstances || undefined;
+/*global Blockly:true */
+/*global getInstances:true */
 
 /// --- Delete rows  --------------------------------------------------
 

admin/blocks/deleteSheet.js

@@ -1,6 +1,6 @@
 'use strict';
-var Blockly = Blockly || undefined;
-var getInstances = getInstances || undefined;
+/*global Blockly:true */
+/*global getInstances:true */
 
 Blockly.Words['google-spreadsheet_delete-sheet_delete-on'] = { en: 'delete in', de: 'lösche in' };
 Blockly.Words['google-spreadsheet_delete-sheet_sheetName'] = {

admin/blocks/duplicateSheet.js

@@ -1,6 +1,6 @@
 'use strict';
-var Blockly = Blockly || undefined;
-var getInstances = getInstances || undefined;
+/*global Blockly:true */
+/*global getInstances:true */
 
 Blockly.Words['google-spreadsheet_duplicate-sheet_duplicate-in'] = { en: 'duplicate in ', de: 'dupliziere in' };
 Blockly.Words['google-spreadsheet_duplicate-sheet_sheetName'] = {

admin/blocks/readCell.js

@@ -1,6 +1,6 @@
 'use strict';
-var Blockly = Blockly || undefined;
-var getInstances = getInstances || undefined;
+/*global Blockly:true */
+/*global getInstances:true */
 
 /// --- Read Cell  --------------------------------------------------
 

admin/blocks/writeCell.js

@@ -1,6 +1,6 @@
 'use strict';
-var Blockly = Blockly || undefined;
-var getInstances = getInstances || undefined;
+/*global Blockly:true */
+/*global getInstances:true */
 
 /// --- Write Cell  --------------------------------------------------