Please add support for Table and Horizontal Rule for nodes in markdown

[s1-ranjan]

It would be nice to extend the node to support for Table and horizontal rule, In markdown format the table can be render using

| Tables        | Are           | Cool  |
| ------------- |:-------------:| -----:|
| col 3 is      | right-aligned | $1600 |
| col 2 is      | centered      |   $12 |
| zebra stripes | are neat      |    $1 |

to render

Tables	Are	Cool
col 3 is	right-aligned	$1600
col 2 is	centered	$12
zebra stripes	are neat	$1
and for horizontal rule by

Three or more...
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Hyphens
***
Asterisks
___
Underscores

to render
Three or more...

Hyphens

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Asterisks

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Underscores

[phase1geo]

I don't plan to support any Markdown within nodes that is outside of text formatting (i.e., horizontal rules and tables).