C# – Consequences of Having Unnecessary References and Usings

I would say that nuget is the best way to handle dependencies.

nuget can manage versions AND automatically download the dependencies from your local nuget server.

It's quite easy to create/configure a local server. Simply create a new empty ASP.NET project and install the nuget-server nuget package (using nuget ;).

That also means that you wont have to check in all dependencies and/or manage their versions using TFS.

Passing a delegate allows the caller instantiating the object to inject custom initialization behavior. Note the configuration(this.settings) call in the constructor code, which executes the behavior provided by the constructor delegate.

I can think of a number of reasons why this might be handy. One hypothetical example might be that of providing platform independence. This is a command line parser; if the parser can be called on Windows or Unix systems, passing a first-class function to the constructor allows the initialization to detect the platform, and adjust the parser settings based on which platform it is running on.

Further Reading
Open-Closed Principle
Inversion of Control