add "nop" and "delete" commands

src/core/Command.h

@@ -8,15 +8,18 @@ class Command
 public:
     enum : uint32_t
     {
-        FOLLOWING_CHAR = 0x1u,
+        FOLLOWING_CHAR =    0x1u,
+        RANGE =             0x2u,
     };
 
     enum : uint32_t
     {
+        NOP,
         FORWARD_UP_TO_CHAR,
         FORWARD_ON_TO_CHAR,
         BACK_UP_TO_CHAR,
         BACK_ON_TO_CHAR,
+        DELETE,
         DELETE_LINE,
         COMMAND_COUNT,
     };