jack exponential volume

The volume scaling for the "software mixer" is linear, this makes it so that the volume doesn't really seem to change until you get it very low, it makes more sense to use exponential volume, below is a change i made that makes the software mixer use expoenential volume.

-Alex

Index: jack.c
===================================================================
--- jack.c (revision 1923)
+++ jack.c (working copy)
@@ -21,6 +21,7 @@
#include "common.h"
#include "log.h"
#include "options.h"
+#include

#define RINGBUF_SZ 32768

@@ -274,7 +275,7 @@
static void moc_jack_set_mixer (int vol)
{
volume_integer = vol;
- volume = (jack_default_audio_sample_t)vol / 100.0;
+ volume = (jack_default_audio_sample_t)((exp((double)vol / 100.0) - 1) / (M_E - 1));
}

static int moc_jack_get_buff_fill ()