[Media_api] Static sysex buffer size

[Roger Dannenberg]

> I've noticed that the sysex buffer is statically sized at 1024 bytes,
> which for many applications is very small.

The fact that the sysex buffer is statically sized at 1024 bytes (I 
think this is referring to the Win32 implementation) should not be 
interpreted as a limitation on sysex message size. Larger messages are 
sent through a sequence of calls, but this is an implementation detail 
that is not visible to the client. -Roger