Move OS module out of backend Javascript into a proper module file. Add normal bytearray to bytearray module. Add read:to method to os module for reading into a bytearray.

#{
	main <- {
		foo <- dict linear:
		foo set: "key1" "val1"
		foo set: "key2" "val2"
		foreach: foo :k :v {
			print: k . ", " . v . "\n"
		}

	}
}