Some refactoring

Nub.Lang/Nub.Lang/input/core/print.nub

@@ -1,7 +1,6 @@
-include "core/string.nub"
+include "core/strlen.nub"
 
 let SYS_WRITE = 1;
-let STD_IN = 0;
 let STD_OUT = 1;
 let STD_ERR = 2;
 

Nub.Lang/Nub.Lang/output/build.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
 nasm -g -felf64 out.asm -o out.o
-nasm -g -felf64 ../input/core/string.asm -o string.o
+nasm -g -felf64 ../input/core/strlen.asm -o strlen.o
 
-ld -o out out.o string.o
+ld -o out out.o strlen.o