Duplicate files

I'm working on a C++ performance research project and I'm using Synfig as a test case. I went through this repo and found some duplicate files:

rendering/sources/icons/group_icon.sif
rendering/sources/icons/layer_other_group_icon.sif

rendering/sources/icons/layer_example_filledrectangle_icon.sif
rendering/sources/icons/layer_geometry_rectangle_icon.sif

rendering/sources/icons/layer_example_simplecircle_icon.sif
rendering/sources/icons/layer_geometry_circle_icon.sif

rendering/sources/layers/circle/circle-alpha-0.sif
rendering/sources/layers/circle/circle-feather-0.sif

rendering/sources/layers/gradient-noise/gradient-noise-black-white-interpolation-cosine.sif
rendering/sources/layers/gradient-noise/gradient-noise-black-white.sif

rendering/sources/layers/star/star-test.sif
rendering/sources/layers/star/star.sif

I'm not sure what's save to remove, so I'll be leaving this list here. If you want me to submit a PR to purge them I can.