ENH: sparse matrix 1-norm estimate

This is my attempt to implement Algorithm (2.4) of Nicholas J. Higham and Francoise Tisseur (2000), "A Block Algorithm for Matrix 1-Norm Estimation, with an Application to 1-Norm Pseudospectra." SIAM J. Matrix Anal. Appl. Vol. 21, No. 4, pp. 1185-1201.

Implementations of this algorithm already exist for Matlab, Octave, R, Python, etc., but I've refrained from looking at their source codes, and instead I tried to implement it using only the publication.  Because the algorithm has a stochastic component, it is less straightforward to test than might be expected.

See also issue https://github.com/scipy/scipy/issues/545 which has been converted from ticket http://projects.scipy.org/scipy/ticket/18

I'm also a fan of some of this stuff http://projects.scipy.org/scipy/ticket/1189 which I think was never merged into scipy, and I ended up re-implementing parts of this for tests.