Modernize build and test infra

Makefile

@@ -0,0 +1,12 @@
+# This stub makefile for a Kaleidoscope plugin pulls in 
+# all targets from the Kaleidoscope-Plugin library
+
+MAKEFILE_PREFIX=keyboardio/avr/libraries/Kaleidoscope-Plugin/build
+UNAME_S := $(shell uname -s)
+
+BOARD_HARDWARE_PATH ?= $(HOME)/Arduino/hardware
+ifeq ($(UNAME_S),Darwin)
+BOARD_HARDWARE_PATH ?= $(HOME)/Library/Arduino/hardware
+endif
+
+include $(BOARD_HARDWARE_PATH)/$(MAKEFILE_PREFIX)/*.mk