move routes into modules (readonly, export, import)

I moved the routes for requests that handle readonly, export or import
requests into seperate modules.

node/routes/export.js

@@ -0,0 +1,53 @@
+var ERR = require("async-stacktrace");
+
+module.exports = function(app)
+{
+  //TODO put this into module
+  //checks for padAccess
+  function hasPadAccess(req, res, callback)
+  {
+    app.securityManager.checkAccess(req.params.pad, req.cookies.sessionid, req.cookies.token, req.cookies.password, function(err, accessObj)
+    {
+      if(ERR(err, callback)) return;
+
+      //there is access, continue
+      if(accessObj.accessStatus == "grant")
+      {
+        callback();
+      }
+      //no access
+      else
+      {
+        res.send("403 - Can't touch this", 403);
+      }
+    });
+  }
+
+  //serve timeslider.html under /p/$padname/timeslider
+  app.get('/p/:pad/:rev?/export/:type', function(req, res, next)
+  {
+    var types = ["pdf", "doc", "txt", "html", "odt", "dokuwiki"];
+    //send a 404 if we don't support this filetype
+    if(types.indexOf(req.params.type) == -1)
+    {
+      next();
+      return;
+    }
+
+    //if abiword is disabled, and this is a format we only support with abiword, output a message
+    if(app.settings.abiword == null &&
+       ["odt", "pdf", "doc"].indexOf(req.params.type) !== -1)
+    {
+      res.send("Abiword is not enabled at this Etherpad Lite instance. Set the path to Abiword in settings.json to enable this feature");
+      return;
+    }
+
+    res.header("Access-Control-Allow-Origin", "*");
+
+    hasPadAccess(req, res, function()
+    {
+      app.exportHandler.doExport(req, res, req.params.pad, req.params.type);
+    });
+  });
+
+};