Issue with mac installation from 0.1.18 -> 0.1.19

[domdomegg]

I've noticed a few issues with the update to 0.1.19:

• models will autodownload even if already present
• the whisper-cli binary isn't called correctly, using the old ./main entrypoint which has been deprecated for whisper-cli (see whisper : rename binaries + fix install ggml-org/whisper.cpp#2648)

I'm happy to raise a PR for this, and plan to do so shortly.