Merge branch 'release/0.6.66' into develop
Remove email validation

Closes #80
Fix tests for base case (no users, no tomatoes)
Minor changes to profile_image helper method
Add better_errors gem
Fix Mongoid::Errors::DocumentNotFound exception
Add high_voltage gem; remove useless unicorn gem

See #83
Update layout management

Now WelcomeController is the only controller showing the big Tomatoes
logo. Footer and header moved to shared/partials and header splitted
between `public_header` (the one with big Tomatoes logo) and `header`.
Add "How to" page

See #83
Fix resource loading failure

If FOG_DIRECTORY (the AWS S3 bucket name) contains dots "." they are
interpreted as subdomains making the certificate for *.s3.amazonaws.com
useless.

Note: this solution uses link to resources in the form
s3.amazonaws.com/<bucket>, it works only for US standard zone buckets.

See #88
Add placeholder content to "How to" page

See #83
Remove adv block

See #75
Add nickname and image_file virtual attributes
Fix user_name helper; update profile_image helper
Update omniauth-twitter to latest version

Closes #73
Add sponsorship page

See https://news.ycombinator.com/item?id=5735965
bump version number to 0.6.67
Merge branch 'release/0.6.67'