[MRH/MP][80863228] Specify the Ruby version
[MRH/MP][80863228] Allow a custom format

- The AG page can pass a custom format for the photo count displayed
when scrolling through images. The default is still `current/total`.
[MRH/MP][80863228] Address PR comments

- Update gem version number
- Remove unused parameter
Merge pull request #7 from primedia/mrh_mp_80863228_photo_count_format

[MRH/MP][80863228] photo count format