5.1.0rc1: Numerous optimizations and bug fixes

What's Changed

• Add command-specific help for alignment options by @lenzo-ka in #422
• Fix pocketsphinx_lm_convert failing due to missing lw/wip parameters by @lenzo-ka in #420
• Add thread-local random number generator for thread safety by @lenzo-ka in #423
• Buffer fixes and dict improvement by @lenzo-ka in #419
• Add external timestamp support to endpointer to prevent clock drift by @lenzo-ka in #421
• Increase phone support to 256 and simplify bitvector operations by @lenzo-ka in #435
• Remove deprecated pygtkcompat dependency from livedemo.py by @lenzo-ka in #442
• Fix heap-buffer-overflow in ps_mllr_read by @lenzo-ka in #439
• Fix stack-buffer overflow in WAV chunk ID logging by @lenzo-ka in #437
• Fix null pointer dereference in ngram_model_read by @lenzo-ka in #438
• Use WAV file sample rate unless user explicitly set samprate by @lenzo-ka in #448
• Update CMU pronunciation dictionary to latest version with deduplication by @lenzo-ka in #444
• Finally maybe fix FetchContent? by @dhdaines in #428
• Optimize endpointer performance by @lenzo-ka in #425
• Bump versions for 5.1.0-rc1 prerelease by @dhdaines in #450

Full Changelog: v5.0.4...v5.1.0rc1