downstream release tag for Gentoo

Squashed commit of the following:

commit 530657a2ee9f3052c15039be26aa3b7c50f37eff
Author: Mickaël Thomas <[email protected]>
Date:   Mon Apr 24 04:32:35 2017 +0200

    Update SDL urbanterror icon

commit 38eeeef3736e57fb3e4bb8bb936a505f08889093
Author: Mickaël Thomas <[email protected]>
Date:   Mon Apr 24 04:01:01 2017 +0200

    Remove non-standalone build and associated code

    Also nukes update server and authorize server code

commit 1875cf4746fd32b89fe4dd3171e40879f407dafd
Merge: 79332363 127464ed
Author: Mickaël Thomas <[email protected]>
Date:   Sun Apr 23 23:03:45 2017 +0200

    Merge remote-tracking branch 'ioquake/master' into urt

commit 79332363cc338ec93c39e1094216e5442c310dd8
Merge: 3d62c0fd 21ee340d
Author: Mickaël Thomas <[email protected]>
Date:   Sun Apr 23 22:19:58 2017 +0200

    Merge pull request #1 from danielepantaleone/urt

    Features from official ioUrT

commit 21ee340d9695feabf751faee0837c6b8780c45cd
Author: Daniele Pantaleone <[email protected]>
Date:   Sun Apr 23 22:06:29 2017 +0200

    Fix usage of C99 only stuff and use tabs/spaces consistently

commit 390bbd3036fbc18eb2fc3f05cd6986a03d2ca180
Author: Daniele Pantaleone <[email protected]>
Date:   Sun Apr 23 21:57:21 2017 +0200

    Remove non necessary Q_strsub and Q_strisub

commit ba6397d87951ce85ef3537059a41357b8560fd86
Author: Daniele Pantaleone <[email protected]>
Date:   Sun Apr 23 16:11:12 2017 +0200

    Mark master servers changes in README.md

commit 1194e9740f9d4f8e27c29dff50ac1f8bd624f819
Author: Daniele Pantaleone <[email protected]>
Date:   Sun Apr 23 16:09:45 2017 +0200

    Add official urban terror engine icon

commit ca43dc3675db4c95415f07bcc33c702b71837fd4
Author: Barbatos <[email protected]>
Date:   Sun Apr 23 16:02:37 2017 +0200

    Force a DNS lookup for the master servers

    In this way server admins don't have to restart their servers when a master server IP changes.

commit 68fe00b28ce02c18d332bc4b2c7ba1a8a4d7c604
Author: Barbatos <[email protected]>
Date:   Sun Apr 23 16:00:06 2017 +0200

    Query other master servers when the main one doesn't respond

commit 42c05f00c645e2f2ed3558998510b711439036e0
Author: Barbatos <[email protected]>
Date:   Sun Apr 23 14:09:44 2017 +0200

    Removed the "missing sound" beep FrozenSand/UrbanTerror4#246

commit 99449b1cb23e17a259eccc3869361eca3efa52c0
Author: Daniele Pantaleone <[email protected]>
Date:   Sun Apr 23 13:57:14 2017 +0200

    Added new mouse acceleration style: cl_mouseAccelStyle 2

commit ee86ab467f1dd014bee16d285080aed4e67e022b
Author: Daniele Pantaleone <[email protected]>
Date:   Sat Apr 22 18:17:18 2017 +0200

    Add Urban Terror master server addresses

commit 4c0193f7e8fb25065f2360133398d5ae00acf10f
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 16:56:22 2017 +0200

    Mark partial string matching in README.md

commit 444f7078eab606cae8a285c0e211465d40a331cf
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 16:51:09 2017 +0200

    Added cvarsearch command to lookup a Cvar by it's partial name

commit 143031a53bb706ea7fd44ba153bef8283c3e2abc
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 16:41:27 2017 +0200

    Better print of multiple maps to avoid possible "slot number" confusion

commit 3646d276393fcbcf5058a3dbe3c468d1b561f7f9
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 14:41:12 2017 +0200

    Added partial mapname matching for map command

commit b32536eb02a1bc90044498b2db7bb33aea00162d
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 10:31:04 2017 +0200

    Added partial player name matching for server commands

commit 013d3ac2a5159300b0536cee526762046f5108ae
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 09:52:13 2017 +0200

    Feature optional reason in server kick command

commit 829ba30c2a90512e24d0f4d7333c8852fc2f56bd
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 09:02:35 2017 +0200

    Fix stopserverdemo command being executed on non-dedicated servers

    This commit also move the call to stopserverdemo in SV_DropClient since we would need to stop the server demo whenever the player is leaving the server, and not when he pushes the disconnect button.

commit 6671d8e29fa6d127882874113a441f692e92a8e8
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 08:50:44 2017 +0200

    Add CMake stuff to .gitignore

commit 3d62c0fdfcc3640cdc0552f2a37793436c1b6786
Author: Daniele Pantaleone <[email protected]>
Date:   Fri Apr 21 18:11:53 2017 +0200

    Added support for Urban Terror 4.x auth system