优化 loop
添加 ++ 的处理
添加对后自增/减的支持
支持取反
fix
Merge branch 'develop' of github.com:jadedrip/silang into develop

Conflicts:
	ast_function.h
Merge branch 'develop' of coding.net:jadedrip/Silang into develop
添加左右位移
添加转义字符的支持
修正函数参数无法赋值的问题
支持函数单返回
补充
Merge branch 'develop' of github.com:jadedrip/silang into develop

Conflicts:
	Silang.cpp
Merge branch 'develop' of coding.net:jadedrip/Silang into develop
整合
优化命名返回
Merge branch 'develop' of github.com:jadedrip/silang into develop

Conflicts:
	ast_let.hpp
实现单命名返回
支持 ":="
coding