Changed DOM structure in editor to be easier to maintain.

There was too many elements sharing the same class (preview/content) so
I changed to ID where appropriate. This required to change two form
builders and CSS as well as the Javascript that was looking for the
classes.
Removed a translation for a symbol in the admin header.

I've tried several text but none really made a difference between admin
menu and going back to the blog.Since I use entypo font within the admin
panel, I thought that maybe one icon could give a nice feeling.

The goal is that the first button is a goto blog public's home link. So
I arbitrarly chose an open book icon. Let's see how it fares and adapt.
Fixed bug with js variable naming and Firefox regression

Firefox doesn't use toElement in the dragevent. Fortunately, both chrome
and firefox uses target to fill the value of the element. Also fixed
issue with naming of variable. Some caching apparently made the thing
working when it shouldn't.
Need an update view for when post update fails

This is similar to create.html.erb where it's only called when there's
an error. Maybe I should rename both to error.html and return them but
it gives an extra condition in the controller which can become
cumbersome.

Maybe a after callback could check for the record and render error...
Fixed issue with box-sizing on Firefox.

Box-sizing still requires a -moz prefix. Weird.
Changed default link color for something easier on the eyes
Safari CSS prefix. Enough said.
Removed obsolete file
Mixed up french and english locale. Oops
Simplified helper

I was repeating the logic twice. Duh!
Removed min-width while in the editor.

The reason why I removed the min-width is because the screen is split in
2 so it's expected that the preview screen can be smaller than 600px.
Script was not saved as part of the post.

I guess it was forgotten since partials had it.
Fixed the Javascript interpreter as first step to solve #15

Right now, I rebuild the whole scrip ton every input change. One of the
problem with doing that is the load that is incremental. One of the
solution would be to purge the DOM so every event bound to the DOM would
be flushed. This would probably give a flicker on the preview.

Since this is programming, I'm not sure there's a best way to do that.
Just made the flash present for now.

I don't want to be stuck in a place where I just want everything to be
perfect. Let's just make the flash apparent and leave it there for now.
I'll have more than enough time to fix everything down the road.
Merge branch 'master' into marmite

Conflicts:
	app/assets/javascripts/admin/editor.coffee
	app/views/layouts/application.html.erb
	app/views/unauthenticated/show.js.erb