[MRH/MP][80863228] photo count format

Story: https://www.pivotaltracker.com/story/show/80863228

- Allow the app using jquery-photoplus to specify a custom format for the photo count.
By default, it is still `current/total`.
- Incremented the gem version number.
- Added a `.ruby-version` file.

Note: We are unable to run the jasmine specs for this gem.