Fix gateway timeout error on PHP wrapper by removing the ending slash before query string starts
Ruby wrapper changes

- Adding client secret to the Ruby wrapper's config file
- Adjusting the OAuth wrapper's API to make the client secret optional
  in case the customer declares it in the config file
- Adding support for detailed stats: Email#opens, Email#unsubs,
  Email#clicks, Contact#stats, List#stats
- Adding sample code for API to list active contacts
- Changing enumeration format for the sample code