我重新思考了下vm, and I found I don't need to implement tail call optimization for that compiler in vm.scm, I only need to implement tail call optimization when bootstrapping in the future. Compiler written in toy

;; 注意
+;; 虚拟机的compiler没有implement tail call optimization
+;; tail call optimization 将会在以后 bootstrap的时候implement
+;; 到时候用 toy language 写compiler生成字节码再用虚拟机运行
+;; 现在的虚拟机只是core， implement最基本的内容