Added accelerometer support on Windows 8 devices.
Fixed little paste error...
Merge pull request #249 from MrHalfman/ticket-194

[#194] Added accelerometer support on Windows 8 devices
[#194] renamed `me.sys.gyro` to `me.sys.hasAccelerometer' and fixed a couple of things
changelog update
removed the new `DefaultLoadingScreen` instance from the global `me` namespace

that also allows to free the related memory if a custom loading screen
is set
use `typeof` when checking if offset is defined
[#59] implemented the `moveUp`. `moveDown`. `moveToTop` and `moveToBottom` functions

Also, swap z index when swapping child through the `swapChildren`
function.

warning : this is barely tested, bugs for sure to be expected :)
[#59] renamed the `propertyToSortOn` property to `sortOn` (shorter is better)
[#59] renamed the `getParent` function to be less confusing and fixed documentation
other tiny documentation fixes
[#59] faster object adding

Surprisingly, calling push is faster :)
[#59] added recursive sorting for child containers
[#159] merged both update loops and probably fixed a bug too (should have been `!obj.updateWhenPaused`)
use `typeof` when checking if defined

I'm also writing 1.000 times "i will not anymore forget to use typeof"
:P
Less math, more fun !