Differentiate "current orientation" and "update orientation".
random rewrite
pending-promise is set on the document
Rewrite orientation change and visibility handling.
always specify 'document' when using 'current orientation ...'
Move 'default orientation' from a browsing context to a document context.
Apply comments from Marcos
Merge pull request #68 from mounirlamouri/gh-pages

Rewrite the updating and reading part of the specification.