- Only test keys when file is encrypted
- Add clHCA_TestBlock to test a frame with the current key
- Move some key detection code to hca_decoder.c and simplify hca.c
detection
- Decrease number of test frames due to increased accuracy of
clHCA_TestBlock
- rename clHCA_DecodeSamples16 to clHCA_ReadSamples16 since it isn't
really decoding
- divide clHCA_Decode into clHCA_DecodeHeader and clHCA_DecodeBlock to
clarify usage
- unify clHCA_IsOurFile0/1 since one would need to call
clHCA_DecodeHeader right after it anyway
- add clHCA_SetKey for easier key handling
- adapt vgmstream wrapper
