Add ConcurrentAsyncEvaluation option

[gumbarros]

This closes #609

[gumbarros]

@Dreamescaper

[Dreamescaper]

I can think of couple of other cases which could be parallelyzed.

• Some built-in functions, like Min/Max.
  I.e. for Max(FuncA(), FuncB()) - FuncA and FuncB could be evaluated in parallel

• Lists, i.e. for (FuncA(), FuncB(), FuncC()) - FuncA, FuncB, FuncC could be evaluated in parallel.

Would it make sense to implement here as well?
Although the flag name would have to be updated, as it's not about binary only anymore.

[gumbarros]

I can think of couple of other cases which could be parallelyzed.

* Some built-in functions, like Min/Max.
  I.e. for `Max(FuncA(), FuncB())` - FuncA and FuncB could be evaluated in parallel

* Lists, i.e. for `(FuncA(), FuncB(), FuncC())` - FuncA, FuncB, FuncC could be evaluated in parallel.

Would it make sense to implement here as well? Although the flag name would have to be updated, as it's not about binary only anymore.

Makes sense if we rename to ConcurrentAsyncEvaluation

[gumbarros]

@Dreamescaper when possible please check the changes

[Dreamescaper]

LGTM :)