Classe: link_widget  - X-Ref

eTemplate Extension: several widgets as user-interface for the link-class

All widgets use the link-registry, to "know" which apps use popups (and what size).
If run in a popup and the app uses no popups, a target will be set, to open a new full decorated window.

The class contains the following widgets:
- link: Show a link to one linked entry specified by an array with keys app, id and optional title and help-message
- link-to: Widget to create links to an other entries of link-aware apps
If an id was set, this widgets creats the links without further interaction with the calling code.
If the entry does not yet exist, the widget returns an array with the new links in the id. After the
entry was successful create, bolink::link($app,$new_id,$arr) has to be called to create the links!
- link-list: Widget to shows the links to an entry in a table with an unlink icon for each link
- link-string: comma-separated list of link-titles with a link to its view method, value is like get_links()
or array with keys to_app and to_id (widget calls then get_links itself)
- link-add:    Add a new entry of the select app, which is already linked to a given entry

<code>
$content[$name] = array(
'to_app'       => // I  string appname of the entry to link to
'to_id'        => // IO int id of the entry to link to, for new entries 0, returns the array with new links
// the following params apply only for the link-to widget!
'no_files'     => // I  boolean suppress attach-files, default no
'search_label' => // I  string label to use instead of search
'link_label'   => // I  string label for the link button, default 'Link'
// optional only for the link-add widget
'extra'        => // I  array with extra parameters, eg. array('cat_id' => 15)
);
</code>

This widget is independent of the UI as it only uses etemplate-widgets and has therefor no render-function.