Add jquery.easytabs plugin

Because the jquery UI tabs are a bit of a nightmare to work with.
Split the profile into separate tabs
Add party and constituency fields to person form
new markup for person page, to suit mockups
first stab at entity-header styling
make form controls on person page match the element they replace
Update selector for person page tabs js
styling for .entity-details tab contents
Merge branch '468-person-page-overhaul' of git.mysociety.org:/data/git/public/popit into 468-person-page-overhaul
less broken looking /person/new page
Make easytabs an AMD module

This makes it work properly with requirejs 1.x
improvements to person page image
less ugly image upload page
Merge branch '468-person-page-overhaul' of git.mysociety.org:/data/git/public/popit into 468-person-page-overhaul
show .delete-photo button on hover
show placeholders in person header
enter edit mode when you click one of the placeholder questions
person toolbar improvements
fix bug where organization was appended to name
hide unimportant properties in view mode if they’re empty