moved get_direction from *_input.cc to input.h

src/input.cc

@@ -0,0 +1,12 @@
+#include "input.h"
+
+game_command get_direction(std::string &str, const char *COMMANDS[],
+                           const int COMMANDS_CNT) {
+        for (int i = 0; i < COMMANDS_CNT; ++i)
+                if (str == COMMANDS[i] &&
+                    i >= game_command::move_north &&
+                    i <= game_command::move_southeast)
+                        return (game_command)i;
+
+        return game_command_panic;
+}