writable folder

I very much welcome the concept of the writable folder.

But I have 2 suggestions.

1. I think this folder should be excluded from git, because its contents do not need to be version controlled. What's more: its contents can and most probably always will be different across different environments.

2. I think CI should be responsible for the creation of this folder upon first run. If i were to edit the location of my writable folder in Paths.php it should be created if non existent. Further more any model that makes use of this folder, may it be logs, session, uploads, ... Should be in charge of creating its own dedicated 'namespace' folder inside of the writable directory.