can't even farm out simple generic array ops

[timsgardner]

We should have a good intrinsic story for array operations, but it sounds like that might take a little while. An obvious stopgap until we can get that is to farm out the most basic array operations to a c# class that can at least preserve type information so we don't have to spastically box stuff:

using System;
namespace ArcadiaHacks
{
	public static class ArrayHelper
	{
		public static T aget<T> (T[] arr, int i)
		{
			return arr[i];
		}

		public static T aset<T> (T[] arr, int i, T val)
		{
			arr[i] = val;
			return val;
		}
	}
}

Even this innocuous class doesn't work well with magic, however:

(def float-ar (float-array 10))

(ArrayHelper/aget float-ar 0)
;; crashes unity!

(ArrayHelper/aget (type-args |System.Single|) float-ar 0)
;; returns 0.0: the correct behavior

(m/faster
  (let [^|System.Single[]| float-ar float-ar]
    (ArrayHelper/aget (type-args |System.Single|) float-ar 0)))
;; throws error

(m/faster
  (let [^|System.Single[]| float-ar float-ar]
    (ArrayHelper/aget float-ar 0)))
;; throws error

(m/faster
  (let [^|System.Single[]| float-ar float-ar]
    (ArrayHelper/aget float-ar (int 0))))
;; throws error

(m/faster
  (let [^|System.Single[]| float-ar float-ar]
    (ArrayHelper/aget (type-args |System.Single|) float-ar (int 0))))
;; throws error

Even if we find some other approach to arrays, these methods should work. If they don't, other stuff won't either.