Document the SDL audio channel mapping

Added SDL_AudioStreamFlush() to the list of new audio stream functions

Reverted changes a970b2ae1bd7 and 4a94743e31fe
I don't want to introduce any regressions with Android TV remote support

Fixed Android joystick detection

audio: Added SDL_AudioStreamFlush().

Don't use DPAD devices as joystick input on Android

Check correct variable for malloc() results.

Fixed bug 3876 - Resampling of certain sounds adds heavy distortion

Simon Hug

Patch that adds [-1, 1] clamping to the scalar audio type conversions.

This may come from the SDL_Convert_F32_to_X_Scalar functions. They don't clamp the float value to [-1, 1] and when they cast it to the target integer it may be too large or too small for the type and get truncated, causing horrible noise.

The attached patch throws clamping in, but I don't know if that's the preferred way to fix this. For x86 (without SSE) the compiler (I tested MSVC) seems to throw a horrible amount of x87 code in it. It's a bit better with SSE, but probably still quite the performance hit. And SSE2 uses a branchless approach with maxss and minss.

Added a staging buffer to the audio stream so that we can accumulate small amounts of data if needed when resampling

Added audio stream conversion functions:
SDL_NewAudioStream
SDL_AudioStreamPut
SDL_AudioStreamGet
SDL_AudioStreamAvailable
SDL_AudioStreamClear
SDL_FreeAudioStream