Improves Controller and Adapter relationship

- Controllers that have adapters are AdaptableControllers
- AdaptableController is responsible to instantiate the proper adapter if needed (string, function or BaseAdapter)
- BaseAdapter is the base class for adapters, allows skipping when passed directly to the controller

src/Controllers/FilesController.js

@@ -1,20 +1,18 @@
 // FilesController.js
 import { Parse } from 'parse/node';
 import { randomHexString } from '../cryptoUtils';
+import AdaptableController from './AdaptableController';
 
-export class FilesController {
-  constructor(filesAdapter) {
-    this._filesAdapter = filesAdapter;
-  }
+export class FilesController extends AdaptableController {
 
   getFileData(config, filename) {
-    return this._filesAdapter.getFileData(config, filename);
+    return this.adapter.getFileData(config, filename);
   }
 
   createFile(config, filename, data) {
     filename = randomHexString(32) + '_' + filename;
-    var location = this._filesAdapter.getFileLocation(config, filename);
-    return this._filesAdapter.createFile(config, filename, data).then(() => {
+    var location = this.adapter.getFileLocation(config, filename);
+    return this.adapter.createFile(config, filename, data).then(() => {
       return Promise.resolve({
         url: location,
         name: filename
@@ -23,7 +21,7 @@ export class FilesController {
   } 
 
   deleteFile(config, filename) {
-    return this._filesAdapter.deleteFile(config, filename);
+    return this.adapter.deleteFile(config, filename);
   }
 
   /**
@@ -49,7 +47,7 @@ export class FilesController {
         if (filename.indexOf('tfss-') === 0) {
           fileObject['url'] = 'http://files.parsetfss.com/' + config.fileKey + '/' + encodeURIComponent(filename);
         } else {
-          fileObject['url'] = this._filesAdapter.getFileLocation(config, filename);
+          fileObject['url'] = this.adapter.getFileLocation(config, filename);
         }
       }
     }