Small editor improvements

[eri0o]

Occasionally when using the Editor I see some stuff that looks "maybe not that hard" and that feels it would improve usage. Whenever I attempt something in this tiny scope I will put here just to not polute elsewhere with tiny changes.

The other reason is just if I am thinking wrong about it someone can just interject here (assuming most people don't follow things in GitHub).

OK, today my first thing in this is adding a button to open the file explorer in the compiled directory.





https://github.com/adventuregamestudio/ags/pull/2133