BF: compare floating arrays with almost_equal. Closes #713056
Revert "BF: (dirty) somehow with upgrade of numpy selected_ids became R/O" -- will provide cleaner fix

reverting so new commit could be easier cherry-picked

This reverts commit 0e440b254daff03987d5cf6bd2846f247243d19a.
BF: numpy 1.7 -- np.where indexes might be read-only, thus operate on a copy then
BF: use inheritance_diagram provided by sphinx on recent sphinx.  Closes: #706534