More 2d nodes

What's Changed

• Nrusch cmake build by @charlesangus in #26
• Add CMake build by @nrusch in #25
• No fastnoise submodule by @charlesangus in #27
• Add Add node by @falkhofmann in #31
• Add Multiply node by @falkhofmann in #33
• Add Gamma node by @falkhofmann in #35
• Add Clamp node by @falkhofmann in #37
• Add ColorLookup node by @falkhofmann in #39
• fixed-black and white clamp on grade by @falkhofmann in #40
• keep option to removeChannels node by @falkhofmann in #41
• Add CopyBBox node by @falkhofmann in #43
• Add Invert node by @falkhofmann in #45
• Add AdjustBBox node by @falkhofmann in #47
• Update README.md by @falkhofmann in #49
• Add Constant node by @falkhofmann in #50

New Contributors

• @charlesangus made their first contribution in #26
• @nrusch made their first contribution in #25
• @falkhofmann made their first contribution in #31

Full Changelog: v0.5.3...v0.5.4