This change required lots of other changes to have it compile. I had to declare all variables from NuEVI.ino used by the menu as extern in a separate header file (globals.h).
Also I moved all defines from NuEVI.ino to a config.h file. I think some of these could be moved back or even moved into menu.cpp.
I declared many variables and functions in menu.cpp as static and moved them around to avoid forward declarations. For simplicity I did some forward declarations anyway.
Some varibles only used in menu.cpp was moved from NuEVI.ino instead of having them as externals.
