Fixes and performance enhancements for Chorus Hub used with Paratext

Chorus Hub: Fixed getting revision of file when it was not changed in the tip revision.
Chorus Hub: Optimized getting repository information when IDs are not needed (1000x speed increase).
After looking into this, I decided I didn't feel comfortable removing the IDs from the returned JSON because ImitationHubJSONService.DechipherJsonString() currently requres it. I did update the comment to better reflect what it will do.