Fix non-cuda compilation with CMake, reoganize domain file names

Created by: sebkelle1

-fixes the compilation of the sedov test case without CUDA -removes dependency on std::exclusive_scan as not all compilers support it yet -cleaner file/directory layout for the cornerstone domain. Instead of a single include directory for all the code, there are now domain/, halos/, tree/, primitives/ and sfc/ subdirectories.