Remove upstream endianness conversion?

[xJonathanLEI]

After inspecting the upstream code, it's found that the library converts between little endian and host endian if they're different. This forces library users to be aware of host endianess.

I'm gonna simply fork upstream and remove the conversion, and instead specifically document that all function inputs must be little-endian.

Alternative solutions considered:

• Explicitly document that function inputs must conform to host endianess

  Not good as it forces users to be aware of host endianess, which is mostly irrelevant today.

• Use target_endian to convert to big endian first if the host is big-endian

  No need to fork upstream, but has unnecessary performance costs on big-endian systems.