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).
It seems like the examples here are not accurate. It seems like it will still be returning id, but it will be blank. Perhapse the code shouldn't return id in the json at all?