ENH: stats: Rewrote stats.obrientransform:

* Vectorized and simplified the computation.  For largeish arrays,
  this gives up to 60 times speed improvement.
* Copy-edited the docstring, and added 'References' and 'Examples'.
* `TINY` changed from 1e-10 to `np.sqrt(np.finfo(float).eps)`.
* Added another test.
BUG: stats: make sure obrientransform doesn't crash using numpy 1.5.x when the shapes of the arguments are not all the same
DOC: update 0.13.0 release notes.
DOC: Add scipy.sparse release notes.
DOC: add authors list to 0.13.0 release notes.

[ci skip]
DOC: stats: Improve the example in the obrientransform docstring to show passing the results to f_oneway
Turned on fancy indexing tests for CSR
Moved indexing utilities to a mixin class
Line wrap
Added a test that caught a bug in CSC/CSR. Details in master branch.
CSR now inherits from IndexMixin
Fixed CSR[1, 2, 3] bug by  extracting indices using method from IndexMixin in
sputils
Modified issequence so that it only returns true for lists/tuples of
scalars.
Limited the last case for the row = int cases. Instead of being a
catch all for CSR[i, *] it now only catches CSR[i, [j, k, ..]]
Turned off assignment tests for now.
Factored out Boolean check from _index_to_arrays() to put at front of
csr __getitem__()
Added todense() function to test_fancy_indexing_boolean() to deal with
cases where CSR.__getitem__() returns a matrix.
Added check for Boolean input in the front of __getitem__(). Otherise,
asindices() sees the Boolean data as zeros and ones.
Reintegrated tolist() optimization that got lost.
Added elementwise getter