Dynamic array concatenation

This release now supports dynamic array concatenation.

For example:

int[] myArr = [2, 3, 4];
myArr ~= 5;
// myArr is now [2, 3, 4, 5]

int myArr2 = [6, 7];

int myArr3 = myArr ~ myArr2;
// myArr3 is [2, 3, 4, 5, 6, 7];