atob/btoa got patched on chrome

Created by: yurydelendik

The https://github.com/Dash-Industry-Forum/dash.js/blob/development/src/lib/base64.js contains:

if (undefined === btoa) {
    var btoa = BASE64.encode;
}
if (undefined === atob) {
    var atob = BASE64.decode;

So Chrome's btoa/atob:

1. are patched by mistake, since var btoa and var atob make variables undefined;
2. patched by wrong function -- shall be patched by encodeASCII/decodeASCII