Fix NaN handling for Visual Studio 2010
Fix NaN handling for Visual Studio 2010

Visual Studio 2010 throws

    error C2124: divide or mod by zero

at compile-time constant divisions by 0.

cicku/libebur128,jiixyj/libebur128,jiixyj/loudness-scanner,jiixyj/libebur128,jiixyj/loudness-scanner