Creating Arrays and PoolArrays
Am I missing something or should there be an easier way to define Arrays and PoolArrays?

I had to do this 
```nim
newPoolVector2Array(newArray(a.toVariant(), b.toVariant(), c.toVariant()))
``` 
which looks ugly.  

I noticed the pool arrays only takes an `Array`, and `Array` only takes `varargs[Variant]` or an `openarray[Variant]`.  So I modified `Array`'s `newArray` to 
```nim
proc newArray*(s: varargs[Variant, `newVariant`]): Array
``` 
and added new constructors for the pool arrays so I can do call: 
```nim
newPoolVector2Array(a, b, c)
```

I can make a PR for this.