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.

{
	foo <- { 42 }
	#{
		qux <- foo:
		bar <- #{
			
			baz <- {
				foo:
			}
			
		}
		
		main <- {
			print: (string: (bar baz))
		}
	}
}