migrate code to AS7, including fucked up arduino import

arduino as a library will not build with -flto. I can't figure it out. so we
waste some space compared to what platformio was building. oh well. there's
still over 1K of space left for programs.

fw/HackSpaceCon_AS7/Arduino/megatinycore/UART.h

@@ -0,0 +1,7 @@
+// We are returning to the conventional name and there is no longer a bloat inducing class layer between
+
+#ifndef HWSERIALNAME_HACK_H
+  #define HWSERIALNAME_HACK_H
+  #include <HardwareSerial.h>
+  #define UartClass HardwareSerial
+#endif