Fixed bug of path location when the manage.py is called outside the project root directory

Fixed bug of path location when the manage.py is called outside the project root directory. The error is caused by *os.getcwd()*, for example, when one of the commands below is executed.

```
python projects/myproject/manage.py scaffold [params]
python ../manage.py scaffold [params]
```

I created a constructor to set the attributes *project base directory* and *project name*.