Adding placeholder tool

[alexlat11]

When dealing with huge workflows, I find myself often needing to use a select tool with comment above as a simple placeholder to come back to that data set as it helps me keep track of everything. It would be nice if there was a tool that didn't really have a function in itself besides allowing one to reference back to that spot. 

I understand one could use a browse tool to achieve the same result but the reason I like using the select tool is because it's a lot easier to work off the dataset with an output arrow whereas with a browse tool I would have to find the previous spot I had the data and delete the browse tool that I was using as a placeholder. 

[patrick_digan]

A true placeholder tool would be nice.