v0.4.0

• 2dc0aad chore: bump versions
• 5120df7 docs: update terms
• 8b4d08b refactor: hide types in implementation
• 5394257 refactor: loosen too strict explicit generics
• 5eb3e14 refactor: remove default values
• 1f62d6e refactor: remove replaced macro
• 45a65f8 refactor: replace explicit state specifier with state allocator generic
• a96396d refactor: shorten trait names