Since Ceres is moving to using GitHub for issues, and the Google
Code URL in the current copyright header will soon become invalid,
update all the headers.
Change-Id: I1fce70375d1bcf098591f07b4d8f01a5c1e0789c
1. Extend the implementation of BlockRandomAccessDiagonalMatrix
by adding Invert and RightMultiply methods.
2. Simplify the implementation of the Schur Jacobi preconditioner
using these new methods.
3. Replace the custom storage used inside Block Jacobi preconditioner
with BlockRandomAccessDiagonalMatrix and simplify its implementation
too.
Change-Id: I9d4888b35f0f228c08244abbdda5298b3ce9c466
Sameer Agarwal