Fixed flowing issues with textarea

Still learning to do proper flowing elements. The main takeaway is that
you should always specified display: flex on parent element. This means
that children will be flex-enabled. Not specifying display: flex will
lead to wasted hours on stupid things like wondering why height: 100%;
and flex: 1 100% aren't working at all.
Removed obsolete files

Responsive will be reimplemented in a different matter since I'm using
CSS flexbox.
Made I18n files more structured so it's easier to navigate.

This fix #11 by applying recursions in the locales folder. This allow
for an easier to navigate the locale data.

I18n reflects controller structure. That means that if you see a
translation in admin::posts#index, it will be found in
locales/admin/posts/{language}.yml
Fixed many small I18n issues and missing labels
Added error handling in partials and some fix.

Partials controller was still looking for old form value from the Engine
era. Oops. Also, I added the same error mechanism the post form has.
Removed JS exceptions. Fixed Partials system

So now the partials behave like the images. There's some glitches going
on with the loaded partials as it has to refetch the partial (even if
it's a 304, it will refetch from cache). So this is something that might
need tweaking for partials and images. Don't know yet so I'm leaving
this without issue.

Partials now have an overlay that gives user a feeling that drag is
possible.
Fixed small issue with listing in partials. Added a top margin in the partial editor as well.
Fixed some CSS and JS glitch with the editor.

There seems to be a bug when the editor is being loaded. Previous commit
removed all exceptions but rendered the editor useless. Now, I
reintroduced some of the previous code and there's still one exception
that needs to be handled. I'm not sure if that exception can be avoided.
Further inquiries will be needed.
Fixed issue with returned value on partial save

Chaining was done in a way that instead of returning a partial, as I was
expecting, it was returning a boolean value.
Merge branch 'master' into marmite

Conflicts:
	app/assets/stylesheets/admin/editor.css.scss
	app/forms/admin/post_builder.rb