increase max limit of bars to 512 per channel (#636) previously this was 512 max total, this is now 512 per output channel for raw it was only 256 total due to a bar_spacing of 1 used in the calculation this is also fixed so if stereo output is configured there can be 1024 bars the limit is in the audio input buffer for the FFT for higher sample rates a higher limit is theoretically possible, this can be looked at later if the intereset is there sdl_glsl output is still limited to 512 due to a limit on uniforms in openGL, there are ways to resolve this if needed (look at the android shader). But that would break all existing shaders.