User contacts

Cache used to prevent slow response on autocomplete
Fix ui/text_mgr.js for on-the-fly texts testing

Backends use raw texts instead of JSON encoded texts now
Fix a missing check in wrapper.php
Fix PttReader

Now supports grabbing links from multiple pages
Use custom jquery widget for displaying facebook group members
Fix a bug and add some error detection codes

$response['new_status'] may be an empty string. Users::setUserStatus()
shouldn't be invoked then
Group member chooser functionality done
index.php: fetch the contact name when page loaded