Finite Differences + first solvers

configure.ac

m4/ax_blas.m4

m4/ax_boost_base.m4

m4/ax_boost_iostreams.m4

m4/ax_boost_program_options.m4

m4/ax_boost_unit_test_framework.m4

m4/ax_cuda.m4

m4/ax_eigen.m4

m4/ax_lapack.m4

m4/ax_suitesparse.m4

src/FiniteDifference/Average.hpp

src/FiniteDifference/Derivative.hpp

src/FiniteDifference/FDScheme.hpp

src/FiniteDifference/FDScheme_unit_tests.hpp

src/FiniteDifference/eq.hpp

src/FiniteDifference/eq_unit_test.hpp

src/FiniteDifference/util/common.hpp

src/FiniteDifference/util/common_test.hpp

src/Makefile.am

src/Matrix/SparseMatrix.hpp