Verifying if the integrate class GaussLegendre works correct, not satisfying results yet.
Header and source for Integrate class, also including GaussLegendre subclass.
Header and source for lib from FYS3150 home page.
Tested GaussLengendre solver with some test integrals from FYS3150 textbook, where solutions where given.
Made some changes in order for the Gauss Legendre interator to work.
Added source and header files.