Projucer: Added functionality to "+" button

As the code of many of the excellent tutorials are all in just in header file, and it appears this coding style is preferred in some cases, how about adding a few options to to the File Explorer “+” button?

When a user has selected a cpp or header file in the file explorer, there would then be at least one new option;

  1. “Add new Component class in this file”,

and if a pair of matching named files (header and cpp) are detected, then also this option;

  1. “Add new Component class class split between this pair of cpp and header files”

On a side note, it was not clear to me when I started, and even the most helpful “The Audio Programmer”, who has some excellent Youtube tutorials, also as unclear that if you want to add a new Component class in existing project, you should click “Source” first or the newly created file or files, will be placed outside group of files and has to be dragged back in.