Add endstops, light_sensor, test, many fixes

- Added endstop and light_sensor module
 - Improved configuration by splitting wiring configs to boards.h
 - Added a unit test for argument parsing
 - Fixed many smaller bugs

src/modules/help/help.cpp

@@ -1,3 +1,5 @@
+#include "config.h"
+#ifdef HELP
 #include "help.h"
 
 void help_setup()
@@ -68,4 +70,5 @@ void help(String command)
     Serial.println(F("<d>                            - a decimal integer."));
     Serial.println("");
     Serial.println("--END--");
-}
+}
+#endif