allow access to PerfData objects
Merge pull request #49 from friedmud/perf_log

allow access to PerfData objects
fix comment
initial file infrastructure for supporting Eigen sparse linear solvers
working vector implementation
working vector implementation
intiial vector, partial implemenation
EigenSparseVector initial implementation
EigenSparseMatrix initial implementation
forgot to remove a libmesh_not_implemented()
hackery to avoid MatType collision
initial linear solver support
fix for --enable-complex
Merge pull request #50 from benkirk/eigen_solver_package

Initial implementation for #44
leave laspack ahead of eigen until the latter implementation is more complete
simpler fix for MatType debacle (#44)
use AC_CHECK_HEADERS to make sure Eigen is usable
Fix for ML/PETSc coupling debacle.

Turns out ML was keying off our 'HAVE_PETSC' preprocessor macro defined previously in configure by autoheader.  Fix is to #undef that before including the ml_include.h file in AC_CHECK_HEADER.
Taking libmesh-specific comment out of eigen.m4

I'm planning to swipe a copy of this for some other projects and I'd
like to keep it in sync.
Bugfix for enableeigen='' case