Announcing Eigen 0.9, beta release (1.0 should follow in 1 month,
after Eigen has been tested in real apps).

Changelog to previous svn commit:
- big API simplification for easy linear solver
- now fixed-size classes never cause dyn mem allocs (thanks valgrind)
(you can even solve systems of equations without any dyn mem alloc)
- lots of fixes for complex numbers, now everything should work with
T == std::complex
- more fixes, more cleanup, more dox