Create markdown-cn.html.markdown

initiate
Updated the file head
Update markdown-cn.html.markdown
2nd para
halfway
Finally Done
Proofread and checked style
typo correction
Footnote corrected
Update markdown-cn.html.markdown
Changed filename
updated the filename into learnmarkdown-cn.md
Merge pull request #666 from FZSS/master

[markdown/zh-cn] Chinese Translation for Markdown