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]
quad: node-to-node deltas now member of quadrature
quad: first adjustments to base sweepers
quad: remove unused parameter
quad: rename member variables and getters

using naming convention of rest of codebase
quad: removing traits; minor fixes
fixing GCC compilation

why does clang not complain? o.O
quad: removing traits & boilerplate code

everything should still work as before
sweeper: adjusting IMEX sweeper to new quadrature

also adjusted AdVec Vanilla SDC example

note: only vanilla_sdc compiles and runs
sweeper: removing three node-methods and reinline the logic into sweep
imex sweeper: fixing @memmett's comments
IMEX: Fix predict.  Sweep is still a WIP.

Signed-off-by: Matthew Emmett <memmett@gmail.com>
IMEX: WIP. Begin fixing sweep (for Gauss-Lobatto at least).

Signed-off-by: Matthew Emmett <memmett@gmail.com>
quadrature: Add `b_mat` (like the `b` in a Butcher table).

Signed-off-by: Matthew Emmett <memmett@gmail.com>
imex: Flesh out `advance()` and `integrate_end_state()`.

Signed-off-by: Matthew Emmett <memmett@gmail.com>