Fix the webdists, this fixes #170.

Particular problems and how they were resolved:
 - The `fs-extra` module, used exclusively by TokenCacher, didn't have a browser version. I rewrote TokenCacher to not use fs-extra (see fdd4cfc7cc)
 - TokenCacher wouldn't work in the browser anyway due to lack of a file system. I made a shim (`Util/TokenCacher-shim.js`) that implements all TokenCacher functionality as null implementations, this causes `login` to always make a request.
 - Compressed packets couldn't be parsed because neither node's Buffers nor zlib were working correctly. Initially I tried to make a browser-only parser class that parses compressed `Blob` packets, but this didn't work out, so I just disabled compression by default.

lib/Util/TokenCacher-shim.js

@@ -0,0 +1,29 @@
+// Shim for the token cacher in the browser.
+"use strict";
+
+exports.__esModule = true;
+
+function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
+
+var TokenCacher = (function () {
+			function TokenCacher() {
+						_classCallCheck(this, TokenCacher);
+			}
+
+			TokenCacher.prototype.setToken = function setToken() {};
+
+			TokenCacher.prototype.save = function save() {};
+
+			TokenCacher.prototype.getToken = function getToken() {
+						return null;
+			};
+
+			TokenCacher.prototype.init = function init(ind) {
+						this.done = true;
+			};
+
+			return TokenCacher;
+})();
+
+exports["default"] = TokenCacher;
+module.exports = exports["default"];