Made some a couple class public along with a few members

[Topkapi]

Hello Sergey,

Thanks for making an awesome library. I have been using it for years and always enjoy working with it.

For my latest job, I had to add some bits to the dashboard but to do that succinctly, I needed to have some of the internal classes from HangFire. Please take a look at the changes and if they are not too much of a bother, you can merge them. Will make it easy for me to keep things fresh.

Thanks.

[odinserj]

@Topkapi, thanks for the PR. Could you tell me more why these changes are necessary and what you are overriding in a derived class?

[Topkapi]

Hi @odinserj,

I wanted to add new custom states and show them on the built in dashboard. I could not do that without making the changes in this PR.

I hope that by making those changes other people will be able to add custom states and show them on the dashboard.

Thanks.

[Powerz]

Hi @odinserj , could you give any update on this PR? Is it going to be merged?