Outsource global variables, Optimize comments

- outsource global variables and objects
    - move from config.hpp to global.cpp / hpp
    - rename config.hpp, thus change all includes
- re-arrange includes -> in source files instead of header

- optimize / make function comment titles more consistent
- optimize comments overall

- add several temporary files to gitignore
- fix unused variable compiler warnings

main/vfd.cpp

@@ -1,4 +1,6 @@
 #include "vfd.hpp"
+#include "config.h"
+#include "global.hpp"
 
 #define CHECK_BIT(var,pos) (((var)>>(pos)) & 1)