sep: v0.5.0

sep.extract() now uses a more correct matched filter algorithm in the presence of a noise array, rather than simple convolution. The conv keyword has been changed to filter_kernel to reflect this, and a filter_type keyword has been added to allow selecting the old behavior of simple convolution.

sep.extract() now accepts a mask keyword argument.

sep.extract() can now return a segmentation map.

Special methods added to allow data - bkg and np.array(bkg) where bkg is a Background object.