entity: fix setReadOnlyValue on IPropertyContainer

[Mikulas]

• setReadOnlyValue internally calls
• internalSetValue which in turn may call
• setValue, which has isReadOnly check

credit goes to @JanTvrdik for this solution

[hrach]

At the beginning I wonder why you are pointing to @JanTvrdik. When I saw it, I understood it. I don't like the implementation! :) Currently, I don't know if it's a better way how to fix it...

[Mikulas]

It seems a little bit like a hack, but it's way better than propagating an $ignoreReadOnlyCheck through the (very deep) call stack. That would also make the API worse, with all those public methods having an additional boolean argument. Static/global ignore flag would also be worse.

[hrach]

Yeah, I know. But the problem is, that it is too recursive. Recursion is fortunatelly stopped, but it may have been stopped a layer earlier.

[JanTvrdik]

@hrach You can always refactor it later, but this is fast, simple and reliable solution for now.