Fix up remaining bugs before release:
* Scheduler calls returning a scalar do not work, so revert
  to using the old API (for norms and inner products);
* iterative solvers in ViennaCL have a bug when called on base
  types, so make sure that solver calls use derived types;
* re-enable buggy tests of yore, since bugs are fixed;
* finish examples.

Yet to do:
* add README for examples and git archive;
* add make dist rule to copy correct README
* update boost_numpy repo;
* integrate examples into Sphinx documentation;
* Debian / Ubuntu packages.