Mark @private methods and properties and private=true

[nnixaa]

Currently, methods and properties marked with @private tag are not ignored and included into the final output. We need a way to control these methods/properties on the client side so that we can remove them or mark as private. So I propose to add a property private which will be resulted in true when @private tag exists on an element.
Code

Result

[nnixaa]

let's ignore the properties marked as /** @docs-private */

[nnixaa]

done in 2.2.0