Merge pull request #274 from wolfmanjm/upstreamedge

remove the definition of max() from nut_bolts.h as it breaks many stl fi...
allow _ for panel custom menu comamnds that need spaces (like G0 X100 Y100 would be G1_X100_Y100)
allow | to separate commands to allow for multiple commands in custom menu
Allow each screen to determine its timeout value before returnign to watch screen
make custom menu and prepare timeouts much longer
allow button press in startup panel screen to go to main menu