revamp change password and cookie system

Admins now generate a remember_token that stays with them until
destruction. This was done to solve a problem in which changing the
password of an admin rewrote its remember_token, breaking the
current_admin method.

The Change Password form no longer requires a current password. Errors
displayed are from the current_admin's errors hash instead of manually
displayed in a flash message.

Also, install the html5shiv and modify the views to use HTML5 tags where
appropriate.
add errors partial, clean up artist views, bio

The bio link now only appears if the artist has info, and only info
attributes of the artist that have been populated are reflected on the
bio page.
force SSL in production config
tweak views