Remove `RSVP.Promise#fail` in favor of `catch`.


After discussion with @wycats and @domenic, it was decided we should remove
`fail` before it enters an official release

- es3 users should use the ['catch'] syntax
- plans are to add a transpiler for people to es5 -> es3 (for finally and catch) etc.
[NICETHING beta] Name anon LinkView CPs

This gets rid of lots of (anonymous function)s i've
been running into lately in the call stack.
Merge pull request #3902 from stefanpenner/remove-promise-fail

Remove `RSVP.Promise#fail` in favor of `catch`.
Merge pull request #3904 from machty/linkview-cp-names

[NICETHING beta] Name anon LinkView CPs