Update pipeline DAG

Signed-off-by: Robert Lin <robertlin1@gmail.com>

doc/dag.dot

@@ -3,20 +3,20 @@ digraph Hercules {
   node [fontname="Roboto", shape=box, style=rounded]
 
   "6 BlobCache" -> "7 [blob_cache]"
-  "0 DaysSinceStart" -> "3 [day]"
   "10 FileDiff" -> "12 [file_diff]"
   "16 FileDiffRefiner" -> "17 Burndown"
-  "1 IdentityDetector" -> "4 [author]"
+  "0 IdentityDetector" -> "3 [author]"
   "8 RenameAnalysis" -> "17 Burndown"
   "8 RenameAnalysis" -> "9 Couples"
   "8 RenameAnalysis" -> "10 FileDiff"
   "8 RenameAnalysis" -> "11 UAST"
   "8 RenameAnalysis" -> "14 UASTChanges"
+  "1 TicksSinceStart" -> "4 [tick]"
   "2 TreeDiff" -> "5 [changes]"
   "11 UAST" -> "13 [uasts]"
   "14 UASTChanges" -> "15 [changed_uasts]"
-  "4 [author]" -> "17 Burndown"
-  "4 [author]" -> "9 Couples"
+  "3 [author]" -> "17 Burndown"
+  "3 [author]" -> "9 Couples"
   "7 [blob_cache]" -> "17 Burndown"
   "7 [blob_cache]" -> "10 FileDiff"
   "7 [blob_cache]" -> "8 RenameAnalysis"
@@ -24,7 +24,7 @@ digraph Hercules {
   "15 [changed_uasts]" -> "16 FileDiffRefiner"
   "5 [changes]" -> "6 BlobCache"
   "5 [changes]" -> "8 RenameAnalysis"
-  "3 [day]" -> "17 Burndown"
   "12 [file_diff]" -> "16 FileDiffRefiner"
+  "4 [tick]" -> "17 Burndown"
   "13 [uasts]" -> "14 UASTChanges"
-}
+}