Improvements to launchpad and rocket code.

lib/navigation.ks

@@ -102,6 +102,9 @@ function BurnTime {
   local lastStage is false.
   // We allow a small tolerance to deal with potential floating point errors.
   until totaldV <= 0.001 {
+    if s < 0 {
+      print "Ran out of fuel with " + totaldV + " dV remaining".
+    }
     local F is stageThrust(s).
     local Isp is stageISP(s).
     local m is stageMass(s).