Moved graphics classes into own namespace, added unit testing with gtest

src/PtouchPrint.cpp

@@ -3,6 +3,7 @@
 #include <spdlog/spdlog.h>
 
 #include "P700Printer.hpp"
+#include "graphics/Bitmap.hpp"
 #include "libusbwrap/UsbDeviceFactory.hpp"
 
 PtouchPrint::PtouchPrint() {}
@@ -35,6 +36,9 @@ void PtouchPrint::run() {
     printer->attachUsbDevice(devices[0]);
     auto status = printer->getPrinterStatus();
     spdlog::info("Detected tape width is {}mm", status.tapeWidthMm);
+    auto bm = ptprnt::graphics::Bitmap<ptprnt::graphics::ALPHA8>(512, 128);
+    printer->printBitmap(bm);
+    //printer->printText("wurst", 1);
 }
 
 unsigned int PtouchPrint::getCompatiblePrinters() {