Merge pull request #85 from torbjoernk/feature/no-boost

using Eigen::Matrix everywhere -- using boost::math::constant::pi
quad: the new and shiny quadrature
quad: adjust tests
reordering quadrature

splitting into separate files in subdirectory

note: just include 'quadrature.hpp' for all the quadrature stuff
tests: moving Polynomial tests into own file
quad: a little template cleanup
tests: examples: first adjustments [skip ci]