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
Added euclidean_distances_argmin
Chunking on both arrays in euclidean_distances_argmin

Chunking is now possible on both arrays in euclidean_distances_argmin.
The default chunking scheme has been tested for various array sizes, and
seem to be at least as fast as euclidean_distances + argmin invocation,
while using a lot less memory (around 50 times).

At the same time, check_pairwise_arrays has been improved to not copy
arrays that have a np.float dtype.
Improved tests for euclidean_distances_argmin
Wrote docstring for euclidean_distances_argmin
[BUG] safe_asarray() converts sparse matrices dtype

When called with a dtype kw argument, utils.safe_asarray() would
not change the dtype of a sparse matrix. This has been fixed.

Unit tests have been created for safe_asarray().
Used safe_asrray() in check_pairwise_arrays()

This slightly shortens the code.
Change signature of euclidean_distances_argmin()

THe function is passed the number of chunks instead of the number of
rows in a chunk.

Replaced custom code by gen_even_slices()
Added pairwise_distances_argmin()

Similar to euclidean_distances_argmin(), but compute distances
with any metric from scikit-learn or scipy.
Optimized euclidean case in pairwise_distances_argmin
Removed euclidean_distances_argmin

This specialized case is useless since pairwise_distances_argmin has been
optimized for the euclidean case.
Minor code cleanup