v0.8.0-alpha1

Changed

• Update vendored trimAl to d89ffc3 (2.0_RC).
• Use scoring-matrices package to get a base for the SimilarityMatrix class.
• Rename backend to platform for all trimmer classes.
• Use trimAl platform-specific code to accelerate computations.

Fixed

• Missing trimmer classes in API documentation.

Removed

• Outdated platform-specific code.
• archspec dependency (replaced by cpu_features used internally in trimAl).