Add SYCL testing of expint

Add markers to forward decls

Add CUDA testing of expint

Fix static variable usage under NVRTC

Add NVRTC testing

Add configurable definition of complex

Add function aliases

Add GPU support to gegenbauer polynomials

Add SYCL testing of gegenbauer

Add NVCC testing of gegenbauer

Add NVRTC testing of gegenbauer

Add GPU support for hankel

Add SYCL testing of hankel

Add NVCC testing of cyl_hankel_1

Add comprehensive NVCC testing

Add NVRTC testing of cyl and sph hankel

Update docs

Fix writing cuda::std::complex<T> to stdout

Add GPU support to hermite

Add SYCL testing of hermite

Add CUDA testing of hermite

Add NVRTC testing of hermite

Add markers to hermite docs