XBMC4Xbox

- Link to my PR: https://github.com/antonic901/xbmc4xbox-redux/pull/2
- This is backport of [#3451](https://github.com/xbmc/xbmc/pull/3451)
- More info can be found [here](https://forum.kodi.tv/showthread.php?tid=158812&pid=1541008#pid1541008)

2013-11-01 New control positioning method

this commit adds a new way to position controls on screen.

<left>
<top>
<right>
<bottom>
<centerleft>
<centertop>
<centerright>
<centerbottom>

on top of that, it also allows you to use percentages instead of absolute values.

note: the old way (posx/posy/width/height) will still work in gotham
note: for label positioning to work correctly, defaults.xml should have no position defined for label.

for more info, please use the forum thread below.

forum thread: http://forum.xbmc.org/showthread.php?tid=176115
git commit: [https://github.com/xbmc/xbmc/commit/a52e...01ae0868f3](https://github.com/xbmc/xbmc/commit/a52edf6fecb8056203d0575150508901ae0868f3)
pull request: [3451](https://github.com/xbmc/xbmc/pull/3451) (PR)