Replace "Project" with "Section"

Mike Potter suggested attaching "Tasks" directly to "Sections" rather than having the intermediate of "Project". After discussing it for a while, I think this makes a lot of sense!

This gives the user the freedom to decide what they consider a project: Is it a Space? Is it a Section? Does that Section have only Tasks, or also Discussions and Documents?

Unfortunately, this change won't have a full upgrade path. Here's what I'm thinking:

• The Task will continue to belong to the same section it was before the update
• The Project type will no longer belong to this feature, but the nodes themselves won't be removed - this will allow users to copy what they need from them and then delete when they're done