Merge pull request #17 from neggro/master

Review each commit, not all of them are very useful
some improvements about setting amount = cost * capacity
renamed Refuels.Add to Refuels.Form, refuels.html to list.html, new.html to form.html, improved refuel.fuel management
missed from previous commit
new specific styles (padding), add overview page as the default page (home), refuels date is stored as timestamp now, new format date util fn, test modal for add fuel from new/edit car page, add help page to settings section, maybe something else (make a diff =))