Managing library and framework dependencies

There are various reasons to join an external project to your own project. Because there are different reasons to include a project (let's call it a subproject, or a module) inside another project (let's call it superproject, or a master project, or a container), there are different types of inclusions geared towards different circumstances. They all have their advantages and disadvantages, and it is important to understand these to be able choose the correct solution for your problem.

Let's assume that you work on a web application, and that your webapp uses JavaScript (for example, for AJAX, as single-page app perhaps). To make it easier to develop, you probably use some JavaScript library or a web framework, such as jQuery.

Such a library is a separate project. You would want to be able to pin it to a known working version (to avoid problems where future changes to the library would make it stop working for your project), while also being able...