ephy-web-view: Remove ephy_web_view_get_title_composite()

This is currently only used to set the window title and it's not
actually needed, since we don't show Loading string in title anymore,
only in the status bar. This is consistent with the title box and tabs
title.

https://bugzilla.gnome.org/show_bug.cgi?id=725649
ephy-web-view: Rename set_loading_title as set_loading_message

This is no longer used to set a loading title, since it's always called
with a URL or NULL. Also make it static since it's only used by
ephy-web-view.c. Remove the public getter since it's unused too.

https://bugzilla.gnome.org/show_bug.cgi?id=725649
ephy-web-view: Remove status_message member

The status message is actually a combination of the loading message and
link message, and both are already members.

https://bugzilla.gnome.org/show_bug.cgi?id=725649
ephy-web-view: Move get_title_from_address to ephy-embed-utils

https://bugzilla.gnome.org/show_bug.cgi?id=725649
ephy-web-view: Move embed-title property to EphyEmbed

Since it's the embed title what it represents. The web view already has
a title property inherited from WebKitWebView.

https://bugzilla.gnome.org/show_bug.cgi?id=725649
Add title parameter to ephy_shell_new_tab_full to create tabs with an initial title

And use it from ephy-session so that when loading the session and not
using delayed requests, you don't see all the tabs initially with "Blank
Page" title.

https://bugzilla.gnome.org/show_bug.cgi?id=725649