Change-Id: I13b2b951297ae81bfab0a7b4991a791ed91d594c
Change-Id: I0ec85218e82d1714279d41f7635104d480fb91c3
unnecessarily complexity in the structure of linear solvers and preconditioners. This is the first step towards cleaning up the Preconditioner interface. 2. Minor tweaks and cleanups to the various linear solvers.