Replace Hashie::Mash with ActiveSupport::HashWithIndifferentAccess.

[dblock]

Replaces #1594, includes a way to set the class name globally.

[dblock]

@namusyaka @marshall-lee @james2m Would appreciate a careful code review and comments/feedback, I'll iterate quickly.

I am a little concerned that we're losing method access, since it probably will affect quite a few people but I think it's the right thing to do.

[dblock]

💚

[james2m]

@dblock thanks for finishing that up, looks similar to what I have locally, I just didn't have time to polish up and complete as I'm traveling until 17th. The cleaned up tests is a big relief too! 😬

[dblock]

You've done an excellent job up this far @james2m, thanks for your big effort!

[namusyaka]

💚 👍
I also agree that method access of parameters isn't good design.

[dblock]

How are we feeling about merging this?

[james2m]

I'm happy with it. Using it in a new app with Rails 5.1 release candidate. If I had more tinkering time I'd probably reorganise the files under /extensions as it feels like a dumping ground right now, but nothing functional.

[dblock]

I merged this, lets see what happens ;)