docs: godocs improvements - clear and concise

feat: Add TransformErr variants

This expands the API to allow an error to be returned in transformation (using the TransformErr function signature).

Internally the logic was generally updated to handle a possible error return. This reduces code duplication, and benchmarking shows no measurable performance loss.

feat: Add SliceFilterTransform to Filter and Transform simultaniously

While reviewing use this appears to be a pretty common process that may be able to benefit from our delayed filter allocations.
That said, because of the Transform operation allocations will always occur. Which does offer simpler inPlace concatenation optimizations.

feat: SliceFilterInPlace accepts multiple slices, with additional opt…

…imizations to all cases of multiple slice usage

feat: API consistency improvements + SliceFilter and SliceSplit to ac…

…cept multiple input slices

feat: Add MapInvert to swap a maps keys and values

feat: Add `SliceDifference` and `SliceIntersect`

These two functions help complete our set operations.  These also are provided using methods to minimize the memory allocations needed.

feat: Add SliceTransformToMap and improved performance

This change adds SliceTransformToMap in order to perform a SliceTransform and SliceToMap in a single operation.
Also included are improvements to a couple specific allocation calcluations, with added testing to ensure capacity is correctly calculated.

docs: Add build status badge to README.md

test: Expand benchmarks with consistent inputs