chore(tslint): add tslint & clean up code

src/plugins/dbmeter.ts

@@ -1,5 +1,5 @@
-import {Plugin, Cordova} from './plugin'
-import {Observable} from "rxjs/Observable";
+import {Plugin, Cordova} from './plugin';
+import {Observable} from 'rxjs/Observable';
 /**
  * @name DB Meter
  * @description This plugin defines a global DBMeter object, which permits to get the decibel values from the microphone.
@@ -33,7 +33,7 @@ import {Observable} from "rxjs/Observable";
   plugin: 'cordova-plugin-dbmeter',
   pluginRef: 'DBMeter',
   repo: 'https://github.com/akofman/cordova-plugin-dbmeter',
-  platforms: ['iOS','Android']
+  platforms: ['iOS', 'Android']
 })
 export class DBMeter {
 
@@ -45,27 +45,27 @@ export class DBMeter {
     observable: true,
     clearFunction: 'stop'
   })
-  static start () : Observable<any> {return}
+  static start (): Observable<any> {return; }
 
   /**
    * Stops listening
    * @private
    */
   @Cordova()
-  static stop () : Promise<any> {return}
+  static stop (): Promise<any> {return; }
 
   /**
    * Check if the DB Meter is listening
    * @return {Promise<boolean>} Returns a promise that resolves with a boolean that tells us whether the DB meter is listening
    */
   @Cordova()
-  static isListening() : Promise<boolean> {return}
+  static isListening(): Promise<boolean> {return; }
 
   /**
    * Delete the DB Meter instance
    * @return {Promise<any>} Returns a promise that will resolve if the instance has been deleted, and rejects if errors occur.
    */
   @Cordova()
-  static delete() : Promise<any> {return}
+  static delete(): Promise<any> {return; }
 
 }