appsdk-bump-app-catalog 777 bumping sdk to 2478-49ba674

sdk commit: RallySoftware/appsdk@f50c562583dfab46cf92e50a67ef4c3cf3e7fc17
author: Andrew Ralston
message: S68217 configurable limit to the number of in flight AJAX requests

sdk commit: RallySoftware/appsdk@6d7191bf2cad5c59e0850a75cb8292068d74a4bd
author: Matt McClellan and Alan Hensel
message: DE21505 - fixed story/defect copy in EDP

sdk commit: RallySoftware/appsdk@dc3f8a16d7b6d23f61537f38c304f8fae24d7341
author: Andrew Ralston and Dave Thompson
message: S68214 make the loading mask configurable and turn off by default for expand batches.