Fixed wrong annotations for android.os.Parcel

Parcel.readString() and Parcel.readStrongBinder() were wrongly annotated to return NotNull. In fact they both can return null and this is often used in Android development.
Fixed wrong annotations for android.content.ComponentName

ComponentName.getClassName() and ComponentName.getPackageName() cannot return null. Also it's not possible to create ComponentName with null packageName or className
Added more annotations for android.os.Message

Message.obtain() (all overloaded variants) never return null.
Merge pull request #307 from eterverda/master

Fixed wrong annotations for android.os.Parcel, android.content.ComponentName and android.os.Message