Adress Gael's comments

* rename _binary_search to _utils
* indent list elements
* use default parameters in examples
Do not use global random number generator
Replace squareform(pdist(*, "sqeuclidean"))

... by sklearn.metrics.pairwise.euclidean_distances
Merge branch 'pr_2822' of https://github.com/GaelVaroquaux/scikit-learn into GaelVaroquaux-pr_2822

Conflicts:
	sklearn/manifold/t_sne.py
Merge branch 'GaelVaroquaux-pr_2822' into tsne