Reorganize steps order

Code was really messy and difficult to read. Now the different
steps/stages can be found in reverse order (from stage 4 to stage 1)
Show registration steps hint on top

Shows a wizard-like layout on top, showing the remaining steps before user
is actually registered
Show a link to 'Lost my password' when registering an already used email
Use appropriate titles on each step

Some steps did not have a title. Now all of them have it