UI context variables

*Title: UI context variables

Incentive:
Makes it possible to check for the type of UI in use from pagelayout and other templates,
this can be used to for instance determine which menus/toolbars to show or perform other logic.

*Documentation:
The context variables should make it possible to change the UI based on the context and component.
Context provides the general UI method in place while component determines the module/part in work.
Having two separate variables allows checking on one or the other (or combined).

The component value will be determined according to the following rules in the following order:
- The name of the currently running module
- The name of the currently running view if 'ui_component_match' is set to 'view' in $Module array (module.php) (optional)
- The 'ui_component' setting in the view definition ($ViewList in module.php) (optional)
- The value set by eZModule::setUIComponentName() in the running module. (optional)

ui_component: The current module or subpart in place, possible values:
              content, shop etc. , i.e any module in the system
              node, subpart of content module
              toolbar, subpart of setup module


The context value will be determined according to the following rules in the following order:
- The default value 'navigation'
- The 'ui_context' setting in the view definition ($ViewList in module.php) (optional)
- The value set by eZModule::setUIContextName() in the running module. (optional)


While the context can contain any string value it is recommended to reuse these standard values:
- navigation:     Navigation on the webpage using urls, this is the default unless changed
                  by module. In general all views that don't change values but only has navigation/selection
                  should use this. for instance content/view, class/list
- edit:           Editing of user input and storing, for instance content/edit, class/edit,
                  these pages should not be interrupted with other forms.
- upload:         Upload of files, e.g. content/upload
- administration: Somewhat similar to 'edit' but generally involves configuration or administration
                  of site. for instance setup/session
- browse:         Somewhat similar to navigation but means navigation for a specific item
                  which is returned to a part of the system, for instance content/browse


The current context and component values can be read by PHP code using
$module->uiComponentName()
$module->uiContextName()

New global template variables:
$ui_context
$ui_component

Also available in the $module_result variable
$module_result['ui_context']
$module_result['ui_component']

*Testing:

*SVN Revisions:
7371