Remove the "fuzzy time" code

It was the start of a neat idea, but it only got used in 3 places,
none of which really needed it.

changes/kill_ftime

@@ -0,0 +1,7 @@
+  o Code simplification and refactoring
+    - Remove the old 'fuzzy time' logic.  It was supposed to be used
+      for handling calculations where we have a known amount of clock
+      skew and an allowed amount of unknown skew.  But we only used it
+      in three places, and we never adjusted the known/unknown skew
+      values.  This is still something we might want to do someday,
+      but if we do, we'll want to do it differently.