feat: 避免缓存的全校课表内中文被转义为 Unicode

添加所有课程循环喵课模式，添加课程列表检测，避免未读取课程时进入死循环，添加退出函数，添加单线程喵课间隔超参数 (#32)

feat: 支持重修选课(cxxk)类别；允许存储账号密码便于一键登录 (#30)

doc: add comments about availability Check

remove debug print

Release v5.1

handle CAS 500 error, fix #24

Delete old Class.txt

Release 5.0 单课程时代

exit when nothing to do

refactor: 改为队列选课，同时只选一门课

feat: Cache the course information for the current semester, close #14

extract course name parse part to main function

skip selected course

lint main.py