Support markdown table

So we can use form to display simple data in table structure.

https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet 

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| Tables | Are | Cool |

| ------------- |:-------------:| -----:|

| col 3 is | right-aligned | $1600 |

| col 2 is | centered | $12 |

| zebra stripes | are neat | $1 |