Change Representation of Private Methods

[madoar]

Private methods and fields are currently marked with an _. This not only looks bad but also has no effect, because JavaScript as of now does not support private fields and methods.

Therefore I propose to remove the _ from the private method names and instead add a short comment to each private method that tells the user that this method is only for internal use. Such a comment could look like the following:

/**
 * *** INTERNAL API ***
 * ...
 */

[plata]

JSDoc has a @private tag. Maybe we can use that?

[madoar]

@private would also work I think.