Fixing tests for numerics

configure.ac

m4/ax_petsc_lib.m4

src/DMatrix/EMatrix.hpp

src/DMatrix/tests/EMatrix_unit_tests.cpp

src/Draw/PointIteratorSkin.hpp

src/FiniteDifference/FDScheme.hpp

src/FiniteDifference/eq_unit_test_3d.cpp

src/Makefile.am

src/Operators/Vector/vector_dist_operators_apply_kernel.hpp

src/Operators/Vector/vector_dist_operators_functions.hpp

src/Operators/Vector/vector_dist_operators_unit_tests.cpp

src/PSE/Kernels_test_util.hpp

src/Solvers/umfpack_solver.hpp

src/Vector/Vector_eigen.hpp

src/Vector/Vector_petsc.hpp

src/interpolation/interpolation.hpp

src/interpolation/interpolation_unit_tests.cpp