Change access modifiers to "protected" to allow overriding behavior

[HeavyMetalPirate]

It would be a neat feat if users could override certain functionality of your API. For example, on a current project I need to override the way how borders are drawn based on a condition involving page breaks. The only way to reach my goal is to override drawRowin Table.class. Since that method is marked as private, I can't implement the behavior required and in consequence I have to implement everything from Table down to Paragraph myself (because guess what, basically all other constructors or functions required are either private or default).

Opening them to protected would allow a lot more flexibility for developers with special requirements.

[Frulenzo]

You are completly right. In other commits we will try to set more mtehods as public because flexibility.