WIP: list-item: basic implementation

[cgestes]

Basic implementation of list-item. For review and comments.

[freeslugs]

@cgestes can you post an image of an example of your changes? eager to see what you've done visually.

[cgestes]

Nothing fancy atm..
the idea is more to gather ideas/comments about what and how to implement list in material-ui.

[cgestes]

I have a ListHeader too, but not pushed.

[jkruder]

I would model it after the list in Material Design. I like the primary/secondary action sections - I would vote to make them elements so the developer can specify whatever s/he wants.

Single, double, triple line variants on the list item are important; maybe a 'type' property similar to the different menu types.

[soda29]

Really useful!

[freeslugs]

I think the bottom border should be optional (probably thinner and closer to google's design), and let's try to center the icons in the list better. keep up the great work, eager to get this merged 😄
reference: http://www.google.com/design/spec/components/lists.html#lists-specs

[hai-cea]

@cgestes Thanks for getting this started. This has been a component that have been high on our priority because it is the root element for a few other components that we'd like to redo - like menus, dropdowns, navs.

I'd like to merge your code in and take it over to finish it out. What are your thoughts?

[cgestes]

This piece of code really needs more work. It is not very useful as it is. Feel free to merge in and improve, but it's ok if it's not merge as it is.

I will improve it slowly.

To be done property it seems that we need flex containers.

[hai-cea]

Replaced by #836