do not allow to create a box with same login
make style more cozy like
add fonts
improve edit box styling
improve box edition ui
improve design
improve mail styling
improve mail style: background + attachment box
debuglayout
mark import as failed when credentials are wrong
add no mailbox message when there is no mailbox created
add confirm dialog before deleting a mailbox
route fetch-new returns json response instead of plain text
debug new message retrieval
better error handling
Merge branch 'feature/design' of github.com:mycozycloud/cozy-mails into feature/design

Conflicts:
	client/app/styles/main.styl
	client/public/stylesheets/app.css