Update xterm dep to use master

Active bug fixing is happening, it should be tested

npm-shrinkwrap.json

@@ -422,8 +422,8 @@
     },
     "xterm": {
       "version": "0.33.0",
-      "from": "xterm@latest",
-      "resolved": "https://registry.npmjs.org/xterm/-/xterm-0.33.0.tgz"
+      "from": "https://github.com/sourcelair/xterm.js/tarball/master",
+      "resolved": "https://github.com/sourcelair/xterm.js/tarball/master"
     },
     "yauzl": {
       "version": "2.3.1",

package.json

@@ -33,7 +33,7 @@
     "vscode-debugprotocol": "1.9.0",
     "vscode-textmate": "1.1.0",
     "winreg": "1.2.0",
-    "xterm": "^0.33.0",
+    "xterm": "https://github.com/sourcelair/xterm.js/tarball/master",
     "yauzl": "2.3.1"
   },
   "devDependencies": {