Support of Numpy needed for arr-scan defined in _sane.c with new distribution

Numarray seems no more available, so moving to numpy is needed if you whish to access to 16bit arrays. Unfortunatly, I do not succeed for colors 16bits, a bug to investigate seems to exist in the epkowa driver. 
Modifications done are all related with numpy (numarray remains possible at compilation time) and support of colors array (at less 8bit ones); added a function checkArraySupport allowing to get informations at run time on the array support.

Thank to all people who have worked in pillows.
jfrancois