Renamed ServiceHelper to ServiceExecutor

1. Renamed ServiceHelper to ServiceExecutor and updated class
description
2. Renamed private member “serviceHelper” to “serviceExecutor “ in all
Service classes.
3. Introduced new ServiceHelper class to support common auxiliary
operations required across multiple services.  Updated
getByCustomView() methods to use ServiceHelper class.

4. Miscellaneous: removed a few no longer used Strings from ApiData.java
Introduced new ServiceHelper class

Introduced new ServiceHelper class to support common auxiliary
operations required across multiple services.
Merge pull request #35 from mdanilkis/master

Renamed ServiceHelper to ServiceExecutor