Added iOS8 notification action support

https://github.com/duccio/ApnsPHP/issues/63
Added sCategory as protected variable
Merge pull request #64 from arzynik/master

Added iOS8 notification action support
Update README.md
Update README.md
Fix setCustomProperty() to respect apple namespace
Merge pull request #70 from jetwitaussi/master

Fix setCustomProperty() to respect apple namespace