Implements #189 using density to estimate radius

applications/gui/src/camera.cpp

applications/gui/src/media_panel.cpp

applications/reconstruct/src/ilw/ilw.cu

components/common/cpp/include/ftl/exception.hpp

components/renderers/cpp/include/ftl/cuda/intersections.hpp

components/renderers/cpp/include/ftl/cuda/normals.hpp

components/renderers/cpp/include/ftl/render/splat_render.hpp

components/renderers/cpp/src/normals.cu

components/renderers/cpp/src/splat_render.cpp

components/renderers/cpp/src/splatter.cu

components/renderers/cpp/src/splatter_cuda.hpp

components/rgbd-sources/include/ftl/rgbd/channels.hpp

components/rgbd-sources/include/ftl/rgbd/frame.hpp