Report query timing and reliability in the R client, bump to 1.4.9000

- bump the version to the dev version 1.4.9000
- measure the client-side duration of every API request and report it
  as a queryDuration column (and in the verbose log)
- warn when the server cut a search short (timeExceeded) or when a
  request failed, instead of silently returning 0 counts
- disable the curl low-speed abort, which kills transfers with less
  than 1 byte/s after 600s regardless of the request timeout

Change-Id: I841e928ce07e56b00ad794022343044595f0db47
diff --git a/DESCRIPTION b/DESCRIPTION
index de0a462..44b8d3d 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: RKorAPClient
 Type: Package
 Title: 'KorAP' Web Service Client Package
-Version: 1.4.0
+Version: 1.4.9000
 Authors@R:
     c(person(given = "Marc",
              family = "Kupietz",