subtasks now use swimlane with title matching parent lane title

As discussed in #1953 this is required to handle two-board scenarios correctly.

client/components/cards/subtasks.js

@@ -20,7 +20,13 @@ BlazeComponent.extendComponent({
     const crtBoard = Boards.findOne(card.boardId);
     const targetBoard = crtBoard.getDefaultSubtasksBoard();
     const listId = targetBoard.getDefaultSubtasksListId();
-    const swimlaneId = card.swimlaneId;
+
+    //Get the full swimlane data for the parent task.
+    const parentSwimlane = Swimlanes.findOne({boardId: crtBoard._id, _id: card.swimlaneId});
+    //find the swimlane of the same name in the target board.
+    const targetSwimlane = Swimlanes.findOne({boardId: targetBoard._id, title: parentSwimlane.title});
+    //If no swimlane with a matching title exists in the target board, fall back to the default swimlane.
+    const swimlaneId = targetSwimlane === undefined ? targetBoard.getDefaultSwimline()._id : targetSwimlane._id;
 
     if (title) {
       const _id = Cards.insert({