Switched to C++11

Also added a separate C++ build rule to avoid an error when sending the C++11 flag to c files
Implemented menu and all functionality

Menu now fully works. You can use the up and down arrows to change what displays on lines 1 and 2. You can also hit the select button to go into current limit setting mode. Clicking the up button switches between PS A and B. Clicking the down button takes you into adjust mode. Now the up and down arrows select among a number of current limit values. Clicking the select button asks if you want to save. Hitting the up arrow saves and any other button does not. Also hooked up the actual current limit function. Drawing current greater than the limit shuts down that supply and turns on the status LED. For now you have to reset to get out of shutdown.