Changes in PyQwt-4.2.3:
- support for SIP-4.7, and PyQt-3.17.3.
- support for the N-D array interface specification
  ( http://numpy.scipy.org/array_interface.shtml ) allows to copy data out
  of NumPy arrays without enabling support for NumPy during the compilation
  of PyQwt.
- the iqt module also supports an interactive Python session without the
  help of the GNU readline module.
- removal of a huge memory leak in the conversion from an array to a QImage.
- fixed crashing of MultiDemo.py when a numerical Python extension has been
  installed but PyQwt has not been built with support for that extension.
- when anynumpy.py fails to import any numerical Python extension, it pops up
  a message box showing where to get NumPy.
- the latex sources for the documentation (a Debian requirement).

