Production release 4.9.31

Fixed bugs:

• only one FeedEater job should run at a time #1087

Closed issues:

• FeedVersionInfo filtering: FeedVersion, Feed, and Type #1098
• GTFS Statistics: All filenames #1095
• StopTransfer: Transfers between stations #985

Merged pull requests:

• FeedVersionInfo: query_params #1099 (irees)
• Feed version info controller updates #1097 (irees)
• GTFS Statistics: improved filenames #1094 (irees)
• update mail gem #1092 (drewda)
• updating gems, including Sidekiq and Redis libraries #1090 (drewda)
• Production release 4.9.30-2 #1089 (drewda)
• only one FeedEater job should run at a time #1088 (drewda)
• GTFS Graph Refactor #1037 (irees)