blok 0.0.23

Types and traits for graphlike 3D arrays, designed for visual thinkers.
Documentation

# blok 0.0.30 TODO:

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## General code
- [ ] Source files cleaned up 
- [ ] Unit tests reorganized (only helpers get local unit tests)
- [ ] Documentation improved
- [ ] Errors handled (thiserror)
- [ ] Optimization (not too dry that I'm repeating checks)
- [ ] finish missing methods
- [ ] Function chain for connections
- [ ] 1-based indexing to make lengths vs. indexes easier? 

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## types
- [ ] Transformations 
- [ ] For each (supply functions that use `l`, `r`, `b` to do something with the block)

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## block
- [ ] `disconnect` method for Block trait to allow `remove`
- [ ] Hide "connect", "clone", and other behavior behind features
- [ ] CreationInstruction factories

### layer 
- [ ] tumble_90/180/270

### stack 
- [ ] offset_xyz 
- [ ] collapse 
- [ ] Vertical slices for partial ref

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