Support for alternate markdown table notation

[princefishthrower]

Following this issue thread https://github.com/themsaid/ibis/issues/27 it appears that the following type of markdown tables are supported:

Command	Description
Test	Test

i.e. raw format:

| Command | Description |
|---------|-------------|
| Test    | Test        |

However, the following format is not supported:

Short Flag	Long Flag	Description
-l	-	Show Results in long format

i.e. in raw code format:

|**Short Flag**   |**Long Flag**   |**Description**   |
|:---|:---|:---|
|`-l`|<center>-</center>|Show Results in long format|

This format is valid markdown that works here on Github, but when rendered in the PDF, it comes out as a literal string:

I could potentially do a PR to add this new type of parser, but would need some guidance on where to start.

[princefishthrower]

Any update here?