Add Support for uint32 to TinyFS

[morgankenyon]

Add support for uint32's to TinyFS.

[morgankenyon]

It turns out WebAssembly support for unsigned numbers isn't great. WebAssembly doesn't really support unsigned numbers per say. Their docs say:

The types i32 and i64 classify 32 and 64 bit integers, respectively. Integers are not inherently signed or unsigned, their interpretation is determined by individual operations. link

But once an unsigned int32 is compiled down to wat/wasm, it loses its type and becomes a i32. Which seems to mean it's a signed int32.

The following AssemblyScript example:

export function main(): u32 {
  return u32.MAX_VALUE;
}

Compiles u32.MAX_VALUE down to i32.const -1.

(module
 (type $0 (func (result i32)))
 (memory $0 0)
 (export "main" (func $assembly/index/main))
 (export "memory" (memory $0))
 (func $assembly/index/main (result i32)
  i32.const -1
 )
)

So in general, seems like WebAssembly integers are signed.