Fast generic widefield interferometric imager

 WSClean (w-stacking clean) is a fast generic widefield imager. It uses the
 w-stacking algorithm and can make use of the w-snapshot algorithm. As of
 Feb 2014, it is 2-12 times faster than CASA's w-projection, depending on the
 array configuration. It supports full-sky imaging and proper beam correction
 for homogeneous dipole arrays such as the MWA.
 .
 WSClean allows Hogbom and Cotton-Schwab cleaning, and can clean polarizations
 joinedly. All operations are performed on the CPU (it is not specialized for
 GPUs).