Test buildbot.
Move the Mixin MatrixRhsOutput from H2D to hermes common.
Work on Matrix solvers - renaming, adding import from file to SimpleVector, and adding external solver.
CMake changes.
Move a mixin from mixins to matrix where it belongs.
Fix linking.
A few amendments to cmake. 64-bit version works.
Rework ExternalSolver.
Change the comments.
Take out PARALUTION from 01-poisson.
Re-mark the solvers, so that the sub-types match identifiers from the main-type.
Some work on solvers, mainly ExternalSolver.