Set minimum buffer length to 1

DataStream will crash with a byteOffset out of range error if you run the following code using node js and require.js

install node
install requirejs: npm install requirejs
Create an example file with the following: example.js

(function(requirejs){
    requirejs(['./DataStream'],function(){
        var ds = new DataStream();
    });
})(require('requirejs'));

Put example.js in the same directory as DataStream.js
From the command line run: node example.js

Crash

Fix:  Set minimum ArrayBuffer length to 1 when now defined