shell: Implement EvToolbar as an abstract base class

EvRecentViewToolbar and EvMainToolbar can inherit from EvToolbar.
ev-recent-view: Rename list_store to model
ev-recent-view: Change 'self' by 'ev_recent_view'

Make the code conform Evince convention to name objects
ev-recent-view: Use signal handler_id instead of disconnect_by_func
ev-recent-view: Make parameter's names in callback meaningful

Use 'EvRecentView *' in the parameter instead of the generic
gpointer user_data for callbacks.
ev-recent-view: Fix missing casting for EvJobLoad

Instead of accessing the data structure directly, cast to
to the parent EvJob to get the EvDocument.
ev-recent-view: Fix coding style
ev-window: Fix coding style
ev-window: Use 'documents' instead of 'items' in UI
ev-recent-view: Remove unnecessary column in model
ev-recent-view: Remove unneeded EvDocumentModel

Use default values for page and rotation instead of creating
an EvDocumentModel to get the values.

https://bugzilla.gnome.org/show_bug.cgi?id=633501#c23
ev-recent-view: Rename tree_path to make its purpose clearer

Rename from button_press_item_tree_path to pressed_item_tree_path
to make clear the intention of use.

Remove unnecesary use of label and string functions.  Based on
feedback from https://bugzilla.gnome.org/show_bug.cgi?id=633501
ev-sidebar-thumbnail: (re)set current page when updating visible range

The range of thumbnails shown in the side pane is lost when you change
the width. If the user moves one page forward or backward, the thumbnail
view gets updated and correctly shows the current page in the pane.

This patch adds a call to ev_sidebar_set_current_page when updating
the visible view.

https://bugzilla.gnome.org/show_bug.cgi?id=631050
Fix compilation warning on implicit function