[Dlang-internal] Some suggestions for the d language

[Shadowblitz16]

I had some suggestions for the d language that I think would 
improve it a bunch.

1. var keyword for autodetect of auto and mixin.
this is just a optional way of typing auto and mixin. 
automatically detects which one.

2. optional use of <> instead of !() and (). for templates.
coming from the C# language it's my opinion it's easier to type 
and is more readable.

3. coroutines (aka async functions) and yield overloads
being able to execute functions and yield from them...

bool coroutine(bool done)
{
   yield(false      );
   yield(false,    3); //yields for 3 seconds (double)
   yield(false, done); //yields until done is true (bool)
   return true;
}