Use fullscreen element stack instead of fullscreen enabled flag.
Use empty stack instead of 'fully exit fullscreen'.
Merge pull request #58 from mounirlamouri/fullscreen

Use fullscreen element stack instead of fullscreen enabled flag.
Make device-adaptation reference informative.
Add two more examples.
fixed small respec warning
Merge pull request #63 from mounirlamouri/examples

Add two more examples.
Improve readability regarding relationship between current orientation lock and active orientation lock.
Two more re-wording.
Applies Anne's comments