Unify manual feedrate and Fix LCD MANUAL_FEEDRATE (PR#128)

As noted by @o-lampe at https://github.com/MarlinFirmware/MarlinDev/issues/114#issuecomment-136757614 the `MANUAL_FEEDRATE` for Delta Z should be the same as XY.

Marlin/example_configurations/delta/biv2.5/Configuration_adv.h

 // @section lcd
 
 #if ENABLED(ULTIPANEL)
-  #define MANUAL_FEEDRATE {50*60, 50*60, 4*60, 60} // Feedrates for manual moves along X, Y, Z, E from panel
+  #define MANUAL_FEEDRATE_XYZ 50*60
+  #define MANUAL_FEEDRATE { MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, 60 } // Feedrates for manual moves along X, Y, Z, E from panel
   #define ULTIPANEL_FEEDMULTIPLY  // Comment to disable setting feedrate multiplier via encoder
 #endif
 

Marlin/example_configurations/delta/generic/Configuration_adv.h

 // @section lcd
 
 #if ENABLED(ULTIPANEL)
-  #define MANUAL_FEEDRATE {50*60, 50*60, 4*60, 60} // Feedrates for manual moves along X, Y, Z, E from panel
+  #define MANUAL_FEEDRATE_XYZ 50*60
+  #define MANUAL_FEEDRATE { MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, 60 } // Feedrates for manual moves along X, Y, Z, E from panel
   #define ULTIPANEL_FEEDMULTIPLY  // Comment to disable setting feedrate multiplier via encoder
 #endif
 

Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h

 // @section lcd
 
 #if ENABLED(ULTIPANEL)
-  #define MANUAL_FEEDRATE {50*60, 50*60, 4*60, 60} // Feedrates for manual moves along X, Y, Z, E from panel
+  #define MANUAL_FEEDRATE_XYZ 50*60
+  #define MANUAL_FEEDRATE { MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, 60 } // Feedrates for manual moves along X, Y, Z, E from panel
   #define ULTIPANEL_FEEDMULTIPLY  // Comment to disable setting feedrate multiplier via encoder
 #endif
 

Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h

 // @section lcd
 
 #if ENABLED(ULTIPANEL)
-  #define MANUAL_FEEDRATE {50*60, 50*60, 4*60, 60} // Feedrates for manual moves along X, Y, Z, E from panel
+  #define MANUAL_FEEDRATE_XYZ 50*60
+  #define MANUAL_FEEDRATE { MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, MANUAL_FEEDRATE_XYZ, 60 } // Feedrates for manual moves along X, Y, Z, E from panel
   #define ULTIPANEL_FEEDMULTIPLY  // Comment to disable setting feedrate multiplier via encoder
 #endif