Enable Rails autoloading in rake tasks

Then environment task disables, eager loading breaks with Devise
and requiring all needed files would be a mess
Harden account deletion

* Wrap it into a transaction
* Use destroy over delete so dependent destroys get triggered
  and we thus don't fail on the foreign key constraits
* Check if a photos status message actually exists before accessing
  it
* Add missing dependent destroys
Home page, registration page and robots.txt personnalization
Add my aspects link in the header