corrected the formula to calculate the location of
offset pixel in _texture.pyx
minor changes in syntax in _glcm_loop method.
Using round in place of floor in _texture.pyx to calculate the pixel offset.
Merge pull request #935 from neerajgangwar/fix-greycomatrix

Correctly calculate offsets in grey-level co-occurrence matrices
Remove debug print in contribs
Merge pull request #947 from stefanv/build/contribs

Remove debug print in contribs
Use nearest neighbor interpolation and a gray-level color map for plotting feature matches
Merge pull request #948 from stefanv/bug/plot_matches-cmap-interp

Use nearest neighbor interpolation and a gray-level color map for plotting feature matches