Update 'marked.js' and add bootstrap table support

[AdemJensen]

Changes:

• Updated the marked.js from 2013 version to 2019 version. (The markdown grammar is now more strict than the original version)
• Added bootstrap table support so that the markdown editor can finally create a decent table using markdown grammar(Add class "table-responsive", "table-hover", "table-bordered" to the table being processed).

Please notice that once this update is applied, the topic sign '#' must have a space before the content, like this:

• ##[SPACE]Topic2 is approved.
• ##Topic2 is invalid.

[cebarobot]

Maybe we have to change the highlight script too.

也许我们还得改一下 Markdown 高亮的脚本去支持这个特性……

[cebarobot]

新版本的 marked.js 把 \% \\ 之类的符号全部都转义了……这直接导致 MathJax一定程度的瘫痪……