changed: remove code that looks for a .xml when you do a manual movie addition - counterintuitive and unconsistent

fixed: Grouplist controls absorbed mouse wheel up/down even if it couldn't scroll (partly addresses #10954)

fixed: since we now have 20 buffers, we need to use strlen, not a fixed length. thanks to pantaloonix

An incoming announcement will execute the called method but not return a response (nothing over TCP and an empty HTTP 200 response over HTTP)

fixed: pass libswscale cpuflags in CWinRenderer

refactor: Introduce CAddonInstaller/CAddonInstallJob to handle addon installation, ensuring it's done serially (per-addon) and to ensure that we don't attempt to install the same addon simultaneously

(cherry picked from commit a9670bbe0f0a5d51fe91ca68a980ac360b58e43a)

(cherry picked from commit 560fc16c1b684ada175346a3a055f0c802fc88d5)

Squashed commit due to build breakage during code-reshuffle history.

Conflicts:
	xbmc/Util.cpp
	xbmc/cdrip/CDDARipper.cpp
	xbmc/filesystem/Directory.cpp
	xbmc/filesystem/File.cpp

fixed: #11109 - addons with 2 or more extension points only showed the first extension point within the XBMC UI.

use existing <pathsubstitution> in advancedsettings.xml to translate paths on remote Databases to suite the local machine, thx jmarshall again. fully takes care of Ticket #11101

This reverts commit 4e98a514, reversing
changes made to 8d73cbde.