Fixed some problems with demo scripts. Also, all NumPy arrays returned by pyGURLS necessarily have two dimensions (even if one of them is 1).
Improved docstrings on pygurls.pyx.
Fixed the docstring of demo scripts and cpp files.
Added support to one-dimensional NumPy arrays.
The helloworld.py demo now exactly reproduces the results of its C++ counterpart.
Added 1 to class numbers in helloworld.py.
Added a script that runs all others.