Rewrite lib/_http_*.js files with es8 features
Changed vars with let/const where it's needed; Rewrited some JustReturn Functions to arrowFunction; Small mistakes in comments have been corrected;
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Changed vars with let/const where it's needed; Rewrited some JustReturn Functions to arrowFunction; Small mistakes in comments have been corrected;