title: How can I set up my project hierarchy in QtCreator?
body: <p>I'm quite new to QtCreator, so perhaps I left my heart in eclipse-ville, but I can't for the life of me understand how I should be setting up a project hierarchy in QtCreator.  I understand there is an option to create a kind of root project and then from there add sub-projects to it, which makes sense but it leaves me wondering whether or not this is necessary at the time of creating the project, e.g. can I just create a library in one project and reference it later by another project?</p>
  
  <p>I've tried setting up a blanket type of project by creating a new subdirs project and then adding the main program as a subproject, but then how should I add my library project?</p>
  
  <p>Ideally, I'd like to create one project as the main application and reference another project as a library.  Help?</p>