v1.0.0a1

Major changes

• Rework interface to follow sklearn-like patterns. (#226)
• Remove preprocessing module (temporarily until design is finalized). (#226)
• Add KNN regression. (#226)
• Add HMM classifier with categorical emissions. (#226)
• Use Pydantic for better validation. (#226)
• Add datasets module for sample datasets. (#226)
• Split KNN logic across more functions. (#226)
• Better multi-processing for KNN. (#226)
• Documentation rework + switch Sphinx documentation theme. (#226)
• Fix Sakoe-Chiba width calculation. (#226)