/*
Return array of keys from storage
- storageType: *optional* localStorage or sessionStorage
function (storageType) {

            var isStorageType = typeof storageType === 'undefined' ? false : true;

            var key,
                keys = [];

            if (isStorageType) {
                webStorage = $window[storageType];
                for (key in webStorage) {
                    keys.push(key);
                }
            } else {
                webStorage = $window.localStorage;
                for (key in webStorage) {
                    keys.push(key);
                }
                webStorage = $window.sessionStorage;
                for (key in webStorage) {
                    if (keys.indexOf(key) == -1) keys.push(key);
                }
            }

            return keys;
        }