[Evolution] Port Evolution to WebKit2 for 3.21.90

[Milan Crha <mcrha redhat com>]

        Hello,
I'd like to let the users know that we plan to merge the WebKit2 port
branch of the Evolution and thus make the Evolution depend on the
WebKit2 (instead of the WebKit1) for the 3.21.90 development release,
which is planned to be made the next Monday, August 15th. The 3.22.0
stable release is planned a month later, on the September 19th.

The way WebKit1 and WebKit2 work is very different, thus the adaptation
of the code wasn't simple. We expect some fallout and some corner parts
not fully working at the beginning, but we'll try to fix as many things
as possible not only before the 3.22.0 release, but, of course, also
after it.

The reason I write this email is a plea, if anyone willing to help to
test the pre-release version of the ported Evolution to WebKit2 would
dedicate some time and resources to it and give it a try and report any
issues to GNOME bugzilla [1]. It'll be highly appreciated.

Probably the easiest way of getting the development version of
the Evolution is to use some distribution which already provides it.
I'd use a virtual machine with a Fedora 25 (also pre-release, with
possibility of issues from other libraries too) installation [2] (I do
not follow other distributions closely, thus there can be other
distributions available, which may fit other people better). Eventually
use GNOME Continuous images [3], which can provide even more bleeding
edge GNOME. It might be easier than compiling WebKit2 and the Evolution
stack manually. 

Definitely do not use the development version for the production,
neither overwrite your system Evolution with it, thus you'll be able to
return and use the stable release of the Evolution in case anything
goes wrong.

Please remember it's still a development version, where also other
things might not work as expected, though the current focus is the work
on the WebKit2 port, thus the other parts are mostly settled for
the 3.22.0 release.

        Thanks and bye,
        Milan

[1] 
https://bugzilla.gnome.org/enter_bug.cgi?product=evolution&component=Composer&version=3.21.x&short_desc=%5BWK2%5D%20
[2] using the Live image from:
    https://download.fedoraproject.org/pub/fedora/linux/development/25/Workstation/x86_64/iso/
    which can be installed in a virtual machine and updated regularly
[3] description: https://wiki.gnome.org/Projects/GnomeContinuous
    images: http://build.gnome.org/continuous/buildmaster/images/current/