small ui change for wider (100%) tables

Hello,

sorry for the big commit, but the real changes are only these:

https://github.com/makevoid/db_explorer/blob/d6ea83cc39b7d52ac5d7e138e2ebe07443dd0ab4/app/views/layouts/application.html.haml#L39
where I removed the ul and the spans for the horizontal (split) layout

and this css to widen the tables:
https://github.com/makevoid/db_explorer/blob/d6ea83cc39b7d52ac5d7e138e2ebe07443dd0ab4/app/assets/stylesheets/app.css.sass#L68

I tried to get the db "show" page to have a wider, vertical layout.

I think it's good that you used haml for views and sass for css, that makes "view work" easier, but I'm not a lot into bootstrap, sometimes I prefer some custom css, I think i will add a little bit more of it

try it when you have time and tell me what do you think