Feature: field for cost

[alexander-gess]

I had a strange idea. If you add the "cost" in any project or phase of the project (as a tag [cost: 888] or separate input field) - it make possible to summ of costs in the project or phase.

After collecting enough data, you can do a retrospective analysis costs phases / projects. Undoubtedly this feature you need a rare user - but the idea is good for the plugin. It seems to me.

sorry for my bad English (