Update readme benchmarks

I was incorrectly linking to an old build of conflict set, before the
conflict-set name change. I don't know what the regression is from, but
update the README for transparency now.

README.md

@@ -33,25 +33,25 @@ Performance counters:
 ## Radix tree (this implementation)
 
 ```
-New conflict set: 1.285 sec
-                  0.973 Mtransactions/sec
-                  3.892 Mkeys/sec
-Detect only:      1.196 sec
-                  1.045 Mtransactions/sec
-                  4.180 Mkeys/sec
-Skiplist only:    0.539 sec
-                  2.320 Mtransactions/sec
-                  9.281 Mkeys/sec
+New conflict set: 1.660 sec
+                  0.753 Mtransactions/sec
+                  3.012 Mkeys/sec
+Detect only:      1.524 sec
+                  0.820 Mtransactions/sec
+                  3.280 Mkeys/sec
+Skiplist only:    0.844 sec
+                  1.481 Mtransactions/sec
+                  5.926 Mkeys/sec
 Performance counters:
-               Build: 0.0377
-                 Add: 0.0493
-              Detect: 1.2
-              D.Sort: 0.41
-           D.Combine: 0.0135
-         D.CheckRead: 0.219
-   D.CheckIntraBatch: 0.00654
-        D.MergeWrite: 0.319
-      D.RemoveBefore: 0.224
+               Build: 0.0699
+                 Add: 0.0628
+              Detect: 1.52
+              D.Sort: 0.435
+           D.Combine: 0.0183
+         D.CheckRead: 0.37
+   D.CheckIntraBatch: 0.00801
+        D.MergeWrite: 0.473
+      D.RemoveBefore: 0.215
 ```
 
 # Our benchmark