added ability to disable auto-fix process over scripting defines

[am1goo]

It is needed to prevent auto-fix scripting defines if we have to compile/build project over many game stores.

[am1goo]

@rlabrecque what do you think about merge this change to the master branch?

[rlabrecque]

I'd like to bring this in, but I want to clean it up slightly and make it a bigger feature overall. I think starting from what you have to also allow copying SteamManager.cs out of the plugin and into the project would be great too.