Introduced TypedArray objects.

Introduced TypedArray objects.

Added the global constructors:
  Uint8Array, Int8Array, Uint8ClampedArray, Uint16Array, Int16Array,
  Uint32Array, Int32Array, Float32Array, Float64Array.

Implemented:
    - TypedArray(),
    - TypedArray(length),
    - TypedArray(buffer, [start, [end]]),
    - TypedArray(object),
    - TypedArray(typedarray),
    - TypedArray.BYTES_PER_ELEMENT.

    - %TypedArray%.prototype.constructor
    - get %TypedArray%.prototype.buffer
    - get %TypedArray%.prototype.byteLength
    - get %TypedArray%.prototype.byteOffset
    - get %TypedArray%.prototype.length
    - %TypedArray%.prototype[@@toStringTag]
    - %TypedArray%.prototype.set(array [, start])
    - %TypedArray%.prototype.slice([start, [end]])
    - %TypedArray%.prototype.toString()
    - %TypedArray%.prototype.join(separator)
    - %TypedArray%.prototype.fill().

In collaboration with Tiago Natel de Moura.

This closes #264 issue on Github.