actionIDHandler is overwritten everytime serving Recipe

[Toshihiro Suzuki]

This is problematic when user push and pop TVML views. The actionIDHandler could be overwritten with different one afterwards.
https://github.com/toshi0383/TVMLKitchen/blob/master/source/Kitchen.swift#L89

Handler should either

• be set once and shared in rest of app's process,
• or be set once per request.

I think we just choose the first one since it's much simpler.