Directories: should not need to specify for each model

[Vera]

Right now, I specify the directory at the start of each model
Shoud only really be needed at the start, create the right folders and just work from there.
That would make running on different computers easier.

So:

• start with MainDir (this is where you set the actual folder)
• fill that with folders per model
• In each of the models, just do MainDir + 1_1 etc.