Fix packed structs not working if unsafe code is disabled
Fix bugs in JSIL.IsTypedArray and JSIL.IsPackedArray
Implement support for passing an array initializer to JSIL.PackedArray.New
Add extension methods in JSIL.Runtime for getting the TypedArray/ArrayBuffer backing a given array (so that you can pass it to WebGL, etc.)
Add an example of passing packed struct arrays to WebGL