Fall back to Eigen before Laspack.

Issue #224.
Removing some Laspack-specific references from examples.

Issue #224.
Change default Eigen sparse linear solver type to BICGSTAB.

Otherwise, lots of the examples print
ERROR:  Unsupported Eigen Solver: GMRES
Continuing with BICGSTAB

Issue #224.
Use libmesh_example_assert() in miscellaneous_ex3
systems_of_equations_ex{1,2,3,5} nan with the Eigen sparse linear solvers.
reduced_basis_ex1 works with Eigen sparse linear solvers.
transient_ex2 seems to work with Eigen sparse linear solvers.
Merge pull request #240 from libMesh/default_eigen

Default eigen