* Following major foregrounds have been implemented:
  + galactic/synchrotron
  + galactic/freefree
  + galactic/snr
  + extragalacitc/clusters
  + extragalacitc/pointsources
    NOTE: this component needs further refactor, improvements,
          integration and tests

* A Web UI build upon the Tornado framework and its WebSocket function
  is implemented and is already barely usable.
  + The Web interface is beautiful and reasonable
  + The configurations manipulation part performs quiet well

* However, there are also many problems with the Web UI:
  + The layout should be more compact and concise
  + There should be some popup/tooltip to reflect the operation results
  + The console that start the server task is current *BLOCKING* (i.e.,
    synchronous), however, the WebSocket currently (Tornado v4.3) does
    not support coroutine for the "on_message" method, which further
    hampers the problem been solved.

* 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.

XXX/FIXME:
The console task will BLOCK the tornado, which should be FIXED!
However, the `WebSocket.on_message` currently may NOT be a coroutine
(as of Tornado v4.3), so another way should be taken to solve this
problem in order to call the console task asynchronously!