libview: Rename EvView::binding-activated signal as EvView::scroll

EvView::binding-activated is too generic name for scroll key bindings.
Renamed as EvView::scroll and changed to use GtkOrientable instead of a
gboolean.
libview: Use GtkBindings for caret navigation

This allows themes to override the key bindings and API users to move
the caret cursor programmatically using g_signal_emit_by_name.
libview: Do not redraw after a click if cursor position hasn't changed
ev-toolbar: Set history button arrow icons according to locale's text direction

https://bugzilla.gnome.org/show_bug.cgi?id=702585
libview: Notify about caret navigation errors using the error bell.

https://bugzilla.gnome.org/show_bug.cgi?id=702650
Updated Norwegian bokmål translation
libview: merge get_caret_cursor_rect_from_offset and get_caret_cursor_area

Into a single function and use get_caret_cursor_area everywhere.
get_caret_cursor_rect_from_offset() was a bit confusing, because it
didn't return the cursor_rect, but the bbox of the character where the
cursor should be at. The method that actually returns the cursor_rect is
get_caret_cursor_area.
libview: Make sure the cursor blinks after moving it by a click

The cursor blink is reset when the cursor is moved with the keyboard,
but not when positioned with the mouse.
libview: Take page border into account when computing selections
libview: Update the caret cursor after selecting text with the mouse

If there's an active selection move the caret cursor to the location
where the mouse is released.
libview: Text selection using the caret cursor.

https://bugzilla.gnome.org/show_bug.cgi?id=702073
libview: Use GSlice to allocate EvViewSelection

These structs are allocated and deallocated a lot while selecting text
and merging selection regions.
libview: Use prepend + reverse instead of append to create selections list
libview: Do not schedule a redraw when selecting all text

merge_selection_region already invalidates the damaged region.
Updated Kazakh translation
libview: Fix a crash when selecting more than one page

https://bugzilla.gnome.org/show_bug.cgi?id=702874
libview: Make sure we never use negative coordinates in selection rectangle

https://bugzilla.gnome.org/show_bug.cgi?id=702874
libview: Position the caret cursor at beginning/end of the line when clicking outside the line

Position the caret cursor also when not clicking over text if the line
contains text.
libview: Keep the offset inside a line when moving the caret between lines.

https://bugzilla.gnome.org/show_bug.cgi?id=702075
libview: Remove unused in_selection member from SelectionInfo struct

This is currently unused and redundant, to know whether there are
selections we use selection_info.selections.