Composer settings

[naderman]

Some settings like the name and location of the vendor dir should be configurable. We can do this in the project composer.json file but this would lead to confusion when it's packaged up. So maybe a separate config file is necessary.

[Seldaek]

Another note just so it's not forgotten, the autoloader contains some dirname() that should be adjusted if the vendor dir changes.

[Seldaek]

Fixed