Adding functionality to render a table from a HTML file

[Nelwhix]

Completing one of the todos on the readme by adding the functionality to render table from html file. This PR adds a new dependency to the package: golang.org/x/net/html to help with parsing the html.

[olekukonko]

Can we have more test?

[mattn]

Could you please add tests for broken html? Thanks.

[Nelwhix]

@mattn I already added a test for when there are some unclosed tags. What other edge cases should I test for ?

[mattn]

For example:

<tr>
 <td>foo</td>
</tr>
<tr>
 <th>bar</th>
</tr>

[Nelwhix]

For example:

<tr>
 <td>foo</td>
</tr>
<tr>
 <th>bar</th>
</tr>

Okay added that, it returns :

// 	Output: *=====*
	// | BAR |
	// *=====*
	// | foo |
	// *=====*