增加注释：可设置目录标题与上下文的距离

Merge pull request SYSU-SCC#16 from wu-kan/master

Fix SYSU-SCC#17 SYSU-SCC#18

add clickable url of overlead

fix default title

Merge pull request SYSU-SCC#12 from SYSU-SCC/add-help

feature: added instructions for use

Update README.md

Update README.md