Cleanup general.css, SUI to a message at register

terminate() now prints a .ui.error.message in a .center480.ui.segment
general.css: removed useless rules
Moved some header rules from register.css to general
register.php: if logged in redirect and print a .ui.info.message
Various at search.php

Active aside tab is the selected one Fixed #28
.ui.labeled.input is now .icon.input ant its label is an .info.icon
span.small is a bit larger