reStructuredText Compatible Tables [Enhancement]

**Describe the bug**
Was looking to add clear and compatible tables in output of Markdown-preview. Simple rst Tables are the exact match.

**Input**
```sh
+-------+----------+------+
| Table Headings | Here |
+-------+----------+------+
| Sub | Headings | Too |
+=======+==========+======+
| cell | column spanning |
+ spans +----------+------+
| rows | normal | cell |
+-------+----------+------+
| multi | * cells can be |
| line | * formatted |
| cells | * paragraphs |
| too | |
+-------+-----------------+
```

**Output**
[Visit link](https://gist.github.com/dupuy/1855764#tables)