* The original sleep test task "_task()" renamed to "_task_test()"
* Also add the new "startServerTaskTest()" to trigger the "_task_test()"

NOTE/XXX:
The foregrounds simulation requires the configurations, which is
currently obtained from "self.websocket.configs", which I think is a
HACK.  How to better solve this??

* Colorize the logging messages of different level with different colors
* Also add a different icon for each message

Add "updateTaskStatus()" to update the "#task-status" element.

Also add function "getServerTaskStatus()" to get the task status from
the server.

When the configuration form changed, the changed values are synced to
the server and validated.  The validation errors are then sent back to
the client, which set the custom error messages on the corresponding
fields.

* Split out functions "{g,s}etFormConfigSingle()" from
  "setConfigForm()";
* Rename original "setConfigForm()" to "setFormConfigs()", and uses
  "{g,s}etFormConfigSingle()" to simplify;
* Update other places accordingly.

* milligram.css: Remove the "sourceMappingURL"
* main.js: Add "use strict";
* utils.py: Add a TODO task

* Rewrite "configs.js" to be more modular and generic
* Bind functions to button click event
* Implement the function to set form fields to given configuration data
* Implement the function to reset server-side configurations
* Implement the function to load user configuration file on server
* Implement get the configuration data from the server