Add more detail to unhandled exceptions (#279)

* Add exceptions detail

* Added missing packagename

gplaycli/gplaycli.py

@@ -275,7 +275,7 @@ def download(self, pkg_todownload):
 				unavail_downloads.append((item, exc))
 				continue
 			except Exception as exc:
-				logger.error("Error while downloading %s : %s", packagename, exc)
+				logger.exception("Error while downloading %s", packagename, exc_info=exc)
 				failed_downloads.append((item, exc))
 				continue