Add two more types of table to target feature list

[mgielda]

RST supports four table types altogether, adding to list for completeness' sake.

[mgielda]

By the way, which list is the README based on? I assume this:

http://docutils.sourceforge.net/docs/ref/rst/restructuredtext.html

There is a different document which lists directives which are supported out of the box: http://docutils.sourceforge.net/docs/ref/rst/directives.html

And a much shorter one for roles: http://docutils.sourceforge.net/docs/ref/rst/roles.html

So in fact, since my addition is probably not the only one we would need to make to really have a list of all 'missing' features', perhaps there should be separate sub-feature lists, or at least one for directives. After all, tables can be inserted 'inline' without the .. table:: block, or with it, and these are two separate things to be implemented in some sense.

What do you think @seikichi ?

[seikichi]

Thank you @mgielda ! (and sorry for too late reply...).

As you expected, I created the list in the README based on restructuredtext.html and
interpreted text roles pages, I didn't add thouse features in README because there are too many features :-p.

I agree that creating sub-feature lists about directives and roles. I'll update the README in one of these days.