Add implicit ofAny from cast to Future. Remove Futuristic

[gene-pavlovsky]

What do you think about this?
Adds a "wildcard" implicit cast to Future, similar to Promise's "wildcard" ofData<T>(d:T):Promise<T> cast.

[back2dos]

In theory, it's the right idea and the implementation is correct. In practice wild card casts are a bit of a minefield, as evidenced here: https://github.com/gene-pavlovsky/tink_core/blob/f85e6a090a94158868ff1ce110be8b2e83904a08/src/tink/core/Future.hx#L81

Will check what this does to various projects. If @kevinresol and @benmerckx can confirm that it's fine, then we can gladly merge this.

[kevinresol]

I compared the generated code. I see now that returned futures are wrapped in ofFutureObject everwhere. But I think it will work.

[gene-pavlovsky]

@kevinresol maybe it's not so nice to have that extra generated code.
An alternative is to remove the ofFutureObject and use any of the other workarounds here: https://try.haxe.org/#e7C09
What do you think?

[kevinresol]

@gene-pavlovsky I think it is fine. Because normal user shouldn't need to cast from FutureObject

[gene-pavlovsky]

@kevinresol I've fixed the conflicts? Are you ok to merge this?

[kevinresol]

I think we agreed to remove ofFutureObject?

[gene-pavlovsky]

It's been a while, I forgot about this :)

[kevinresol]

Tried on my project and the diff looks good. @benmerckx do you have any comments?

[benmerckx]

@kevinresol No issues here

[back2dos]

Just as a note if anyone else runs into this: as it turns out, this kinda backfired for Haxe 3. All the static extensions for Future<T> now get applied to any T because of HaxeFoundation/haxe#5924

So for example if you have using tink.state.Promised; using tink.CoreApi; then tink.core.Future.or shadows tink.state.Promised.PromisedTools.or. Flipping the usings fixes it, but it's not exactly pretty. Anyway, I think we'd best leave it as is, as this shouldn't affect too many people (i.e. those who use tink_state and PromisedTools in particular and are still on Haxe 3).