Local storage test is flawed.

[danfoley]

this block of code here should be removed from the local storage test:

if ('localStorage' in window && window.localStorage !== null) {
        return false;
}

that is going to return false if something else already is using local storage, even thought it still is available for use. Remove that block and all will be fine.

[danfoley]

see here: https://github.com/Modernizr/Modernizr/blob/master/feature-detects/storage/localstorage.js

[sampotts]

Merged your PR, cheers 👍