Make six an external dependency.
Add python-six as Travis dependency.
Install six from PyPi.  Travis version is too old.
Add rank filter tests as data dir
Fix 16bit rank filter test in python 3.x
Merge pull request #809 from ahojnnes/rank-setup

Fix rank filter tests
Update pip requirements.
Merge pull request #801 from stefanv/six_external

Make six an external dependency.
Add deconvolution module to skimage.

This module add three function to skimage. The `wiener` function is a
simple wiener deconvolution. The `unsupervised_wiener` is a more
sophisticated wiener deconvolution with automatic estimation of
regularisation parameters. The third function is a literal traduction
in python of the rychardson lucy deconvolution of wikipedia.
Rename test to tests
Some improvements to new deconvolution code
Remove anfft and fftw dependency
Use assert_allclose for testing.
Remove __author__ line and add in CONTRIBUTORS.txt
Change copyright to scikit-image team
Add a small note explaining the wiener filter.
Add pdf paper
Inline crandn function.
Whitespace...
Fix the bad results of unsupervised deconvolution.

The initial implementation was simplified to reduce the number of
local variable. Consequently the parameter data.size was wrong. It was
the size of the fourier spectrum, with hermitian property, instead of
the real space size. This should work.

In addition the PSF is now normalized.