Properly wrap AudioBufferManager block writes (#2725)

The memcpy-version of the ABM::write updated the destination and count
but neglected to move the source forward.  If a block write crossed a
frame boundary then the 2nd frame would repeat the data from the first
half of the buffer.

Fix by incrementing the source pointer by the same amount as was written.

libraries/AudioBufferManager/src/AudioBufferManager.cpp

@@ -209,6 +209,7 @@ size_t AudioBufferManager::write(const uint32_t *v, size_t words, bool sync) {
         size_t availToWriteThisBuff = _wordsPerBuffer - _userOff;
         size_t toWrite = std::min(availToWriteThisBuff, words);
         memcpy(&((*p)->buff[_userOff]), v, toWrite * sizeof(uint32_t));
+        v += toWrite;
         written += toWrite;
         _userOff += toWrite;
         words -= toWrite;