contributors logos added to index screen footer
changed hyperlink to funding anchor - added same for the images
old footer removed for index page
removed little underscores appearing between images - caused by link added to images
DOC: Simpler cross-validation iterator doc
2-fold => 2-fold cross-validation
approximately the same percentage of samples
Remove spurious print statements in sample snippets to make the doc easier to follow
Lowercase y and more consistent blank line usage
Revert "CSR matrix support in pairwise_distances_argmin_min"

This partially reverts commit 6a885cca75f27d53967f3fde87f998cb00926dbf.

Sparse matrix support doesn't actually work for Euclidean distance.
Use pairwise_distances_argmin_min function.

Thanks @pgervais.
Use pairwise_distances_argmin_min in examples.
Add pairwise_distances_argmin.
Add tests for pairwise_distances_argmin.
fixed visual indentation errors
fix indentation errors
use spaces in indentation
fix indentation
fix E501: line too long
fixed indentation and visual indentation errors