
ENHANCEMENTS

* calculate both s- and p-polarisation at once in recursive_fresnelcpp

NEW FEATURES

* full field profile under gaussian beam illumination (reflection and transmission)

* C/armadillo interface to cubature for more efficient integration

CLEANUP

* tests using testthat

* simple demos

* check the derivation of fresnel coeffs for T, turn doc into vignette

* write up the matrix transfer method
