Cleanup:

- Support for Numeric and numarray was removed, because it becomes
  difficult to test. The only supported array package is NumPy.

- The Cython modules were updated following recent evolutions in
  Cython. In particular, Cython's numpy.pxd is used for accessing
  NumPy arrays.

- Functions from the standard library module "string" were replaced
  by string methods as far as possible.

Improvements:

- No more platform-specific subpackages for the extension modules.
  They are placed at the same level as the Python modules.

Bug fixes:

- Scientific.BSP: Some operations created nested ParValue objects.
  (Thanks to Kelson Zawack!)