Remove deprecated sendAction

[Kilowhisky]

Implements #264.

There are two caveats about this code.

1. It uses placeholder methods instead of directly referencing the functions because bind(this) would break if the user changed the action attached dynamically. Code could be reduced if this is not a worry.
2. It is not backwards compatible below 1.13.

[RobbieTheWagner]

It uses placeholder methods instead of directly referencing the functions because bind(this) would break if the user changed the action attached dynamically. Code could be reduced if this is not a worry.

@Kilowhisky can you say more about this?

I think we could probably just delete these placeholders, but maybe add checks to make sure they are functions before trying to call them.

[Kilowhisky]

This style was taken from the deprecation RFC for sendAction.

https://github.com/emberjs/rfcs/blob/master/text/0335-deprecate-send-action.md

The stated use is the following:

// if the salute action is optional you'll have to guard in case it's undefined:
      // if (this.salute) {
      //   this.salute()
      // }
      // 
      // Alternatively, you can also define a noop salute function:
      // salute() {}
      //
      // This allows you to remove the guard while provinding an obvious place to add
      // docs for that action.

Its entirely by style. I also did some testing where did a bind(this) directly to the action method and it worked just fine. But that was under testing and i'm not entirely sure about what would happen if someone tried to change action binding after the component was created. I don't think i've ever done this in code but you never know.

Let me know if i should change it.

[RobbieTheWagner]

Makes sense. Thanks for the PR!

[seansellek]

Can we cut a release now that these deprecations have been removed?

[RobbieTheWagner]

@seansellek yeah, I'll try to cut a release soon