libdocument: Add ev_document_text_get_text_attrs()
libview: Get text attributes from backend and save them in page cache
pdf: Implement ev_document_text_get_text_attrs()
update Simplified Chinese (zh_CN) translation
debug: Add support for drawing different debug borders in EvView

When evince is built with debug support, the env variable
EV_DEBUG_SHOW_BORDERS can be used to draw different debug borders in
EvView using different colors. Depending on the value of the env
variable and and the features supported by the current backend, it can
draw bounding boxes of characters, links, images, form fields,
annotations and selection region.
ev-view-accessible: Rewrite get_run_attributes to return the text attributes from the document

https://bugzilla.gnome.org/show_bug.cgi?id=639932
ev-pixbuf-cache: fix the condition for when a new selection is needed

If we don't have a selection surface/region and points has been set, we
need a new selection surface/region even if the scale hasn't changed.
ev-pixbuf-cache: Clear the selection region also when clearing the job selection
libview: Use merge_selection_region passing NULL to clear the selections

This way only the regions affected by the selection are redrawn and we
don't need to schedule a full redraw every time clear_selection is
called.
libview: Fix second parameter type of scroll signal for h, j, k and l bindings

We were still using G_TYPE_BOOLEAN instead of GTK_TYPE_ORIENTATION. It
worked because both are integers in the end.
libview: Add more scroll key bindings to EvView

All keybindings currently used by EvWindow. Having them in the view
makes them available to other EvView users and they can be overriden by
the themes.
ev-window: Remove scroll accelerators

They are handled by the EvView now, we just leave the page up/down accels
so that they still work even when the view is not focused.
previewer: Remove scroll accelerators

They are handled by the EvView now.
ev-window: Use g_signal_emit_by name instead of ev_view_scroll
libview: Deprecate ev_view_scroll in favor of g_signal_emit_by_name
libview: Stop the cursor blink when there are selections active

Even though the caret cursor is not shown while there are active
selections we don't want the cursor blink timeout running and scheduling
redraws.
libview: do not schedule a resize in ensure_rectangle_is_visible

It will be scheduled if the adjustments change.
libview: Use error bell and return early when moving between lines fails
Updated slovak translation
ev-view-presenter: sync callback to update presenter if presentation current page is updated (this is is useful when we change page and the presentation window is focused