Implemented sort by title and url in history service. https://bugzilla.gnome.org/show_bug.cgi?id=699519

Provided support in libepiphany to query the history ordered by
title or url, ascending or descending.
Set the history table sortable by any of the columns.
https://bugzilla.gnome.org/show_bug.cgi?id=699519

After the history service got support for ordering history results
by various columns, update the history dialog to allow sorting.
* override the column header clicked event to change the sorting
order and/or direction
* reload the data from the history service on column header clicks

In case the history window contents are resorted, to avoid freezing
the user interface, do the following:
* register a source to process the url list received from the service
multiple urls at a time, (as many as possible before the next frame
 drawing) by adding them to the model, and freeing the url
* in case the full list is loaded or another sort is requested, remove
the source, and free the remaining list
* as clearing the liststore while it is set to a treeview emits the
row deleted signal for each row, the liststore is set to null before
clearing, it is cleared, and then set again for the treeview
* as setting the model again resets the sort column and indicator
on the treeview, those attributes must be set again.
Remove use of webkit_web_view_set_view_mode()

Embedded view source mode has been removed from WebKit and the view mode
API has been removed from WebKitGTK+.
uri-tester: Use gio async API to parse the patterns file

https://bugzilla.gnome.org/show_bug.cgi?id=730129
Updated Greek translation
Updated Spanish translation
Fix the build with WebKit 2.5

Update to the API changes in WebKit 2.5
ephy-about-handler: Use ephy settings to check if plugins are enabled

Code is simpler and WebKitWebViewGroup will be removed soon
Revert "Fix the build with WebKit 2.5"

This reverts commit d88f713fb1b23014adabe3733dcc724f2722417c.

Unfortunately we can't use WebKitVersion.h from the web extensions API.
ephy-title-box: Fix crash when closing second window

These binding could already have been destroyed. It might be safe to
simply remove the calls to g_clear_object, since they are not needed for
memory management, but then the bindings might not be unbound if a new
web view is set before the old one is destroyed.

https://bugzilla.gnome.org/show_bug.cgi?id=732784
ephy-title-box: Fix a warning when closing window

From some reason it look like the disconnect by sig_id
plot a warning here, since we can to disconnect by func
it better here.

https://bugzilla.gnome.org/show_bug.cgi?id=732784
ephy-title-box: Fix a type
Updated Turkish translation
ephy-title-box: Remove an unneeded style class
build: Bump required GTK+ version

https://bugzilla.gnome.org/show_bug.cgi?id=730598
ephy-window: Use the new support for RTL icons in GtkIconTheme

https://bugzilla.gnome.org/show_bug.cgi?id=730598
ephy-find-toolbar: Use the new support for RTL icons in GtkIconTheme

https://bugzilla.gnome.org/show_bug.cgi?id=730598
ephy-window: Use view-context-menu-symbolic for the gear menu

This is a new, dedicated icon name for this purpose.
See https://wiki.gnome.org/Initiatives/GnomeGoals/GearIcons
ephy-window: The menu icon name changed to open-menu-symbolic
Updated Hungarian translation