fix(common): restore header overflow for smartphones
fix(accounts): avoid error on get_short_name when User has no name
feat(accounts): add User picture field
feat(accounts): add the User's picture field to Edit Personal Info
fix(accounts): change User.picture file format to JPEG

This will reduce final file size without compromising the image quality.
feat(accounts): define specs for User.picture sizes
feat(accounts): add default styles for displaying User.picture
feat(accounts): display User.picture_medium at Edit Dashboard
feat(accounts): add User.picture_small to the header
feat(accounts): add a widget to output User.picture easier
feat(accounts): display a default image when User has no picture
feat(common): define styles Use picture @ header for smartphones
feat(common): add custom front-end for image fields