Several refactors of GUI creation into separate functions where the
function was too large or intermixed different concerns making it hard
to modify.

Add a context menu entry in main game list to host a netplay game
based on saved settings.

Original commit:
commit 91aaa958e6af0275c07b63443938a0be471e0669
Author: Aestek <thib.gilles@gmail.com>
Date:   Sun Jul 24 14:51:37 2016 +0200

Once a tab is selected the focus can be set directly from the page
changed event. However once the tab was shown, the first tab order
control element was given the focus by default. This was fixed by
delaying the action and setting the focus after the default focus
had been assigned.

* Focus "Hash Code" / "IP address" text box by default in "Connect"
* Focus game list in "Host" tab
* RETURN keypress now host/join depending on selected tab
* Remember last hosted game
* Remove PanicAlertT:
	* Simply log message to netplay window
	* Remove them when they are useless
* Show some netplay message in OSD
	* Chat messages
	* Pad buffer changes
	* Desync alerts
* Stop the game consistently when another player disconnects / crashes
* Prettify chat textbox
* Log netplay ping to OSD

Join scenario:
* Copy netplay code
* Open netplay
* Paste code
* Press enter

Host scenario:
* Open netplay
* Go to host tab
* Press enter