ENH: sparse matrix norm
MAINT: copypaste docstring error
MAINT: rename condest to onenormest
TST: allow the test to pass if the lower-bound-estimate is equal to the exact value
TST: seed for random tests
MAINT: clarification of the code, plus more tests
TST: sparse.linalg/onenormest: test return values + don't use deprecated self.assert_
DOC: sparse: onenormest doc details
Merge pull request #2436 from argriffing/condest

ENH: sparse.linalg: sparse matrix 1-norm estimate

This implements 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.