message: Fix issue in sign-extension of memoryDisplayDelegate
  We display the values at an address as byte-sized values. MemoryDisplayDelegate previously did not sign-extend the byte, and thus would never display negative (byte-sized) numbers.
diff: #include "memorydisplaydelegate.h"
  +#include "binutils.h"
  MemoryDisplayDelegate::MemoryDisplayDelegate(QWidget* parent) : QStyledItemDelegate(parent) {}
  @@ -19,7 +20,7 @@ QString MemoryDisplayDelegate::displayText(const QVariant& value, const QLocale&
  retVal.setNum(value.toUInt());
  break;
  case displayTypeN::Decimal:
  - retVal.setNum(value.toInt());
  + retVal.setNum(signextend<int, 8>(value.toInt()));
  break;
  case displayTypeN::ASCII:
  retVal = QChar(value.toInt());
  