Revert "prepare acquireDirect API" - stupid crap

the most POINTLESS plan of all time... acquireDirect.
why? because you gotta fill in the oscBufs anyway, which will take
precious CPU time, so you can't just pass the blip_bufs to dispatch
and hope it'll help by not processing when nothing's happening.

"so disable it when the per-chan osc is up!" NO! we need this for
volume calculation....

"how about rewrite per-chan osc logic?" you know what? I don't have
either the time or the will for that.
now back to Something Else......

This reverts commit 08177d839a.

src/engine/dispatch.h

@@ -23,7 +23,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include "../pch.h"
-#include "blip_buf.h"
 #include "config.h"
 #include "chipUtils.h"
 #include "defines.h"
@@ -588,14 +587,6 @@ class DivDispatch {
      */
     virtual void acquire(short** buf, size_t len);
 
-    /**
-     * fill a buffer with sound data (direct access to blip_buf).
-     * @param bb pointers to blip_buf instances.
-     * @param the offset to the first sample (use this when calling blip_add_delta).
-     * @param len the amount of samples to fill.
-     */
-    virtual void acquireDirect(blip_buffer_t** bb, size_t off, size_t len);
-
     /**
      * fill a write stream with data (e.g. for software-mixed PCM).
      * @param stream the write stream.
@@ -786,12 +777,6 @@ class DivDispatch {
      */
     virtual bool getWantPreNote();
 
-    /**
-     * check whether acquireDirect is available.
-     * @return whether it is.
-     */
-    virtual bool hasAcquireDirect();
-
     /**
      * get minimum chip clock.
      * @return clock in Hz, or 0 if custom clocks are not supported.

src/engine/platform/abstract.cpp

@@ -23,9 +23,6 @@
 void DivDispatch::acquire(short** buf, size_t len) {
 }
 
-void DivDispatch::acquireDirect(blip_buffer_t** bb, size_t off, size_t len) {
-}
-
 void DivDispatch::fillStream(std::vector<DivDelayedWrite>& stream, int sRate, size_t len) {
 }
 
@@ -130,10 +127,6 @@ bool DivDispatch::getDCOffRequired() {
   return false;
 }
 
-bool DivDispatch::hasAcquireDirect() {
-  return false;
-}
-
 bool DivDispatch::getWantPreNote() {
   return false;
 }