Add a menu item under the "Library" main menu. This should open a dialog which allows the user to select the local directory where the library should reside. A suggestion should be made (like "/home/user/Documents/Box/Library"). The dialog should also contain some text to explain what this is all about. Once the user fires the "Accept"/"OK" button, then the directory should be checked: it may have to be empty, otherwise the user may be asked to import it, e.g. "The directory you selected is not empty. Would you like to import it?". While it is not clear how to implement import functionality (we may first exclude this), we should create the library by checking out a Mercurial repository in Bitbucket, at https://bitbucket.org/franchin/boxer-library. After that, Dox should be aware of this extra location. And Box should be called with the appropriate flags to allow including content from the library (basically, "-I path/to/lib").
