axel: add --HEAD

[axel in github](https://github.com/emiraga/axel)
[Branches](https://github.com/emiraga/axel/branches)

* [x] Add --HEAD all new features functions
 * Unicode progress bar (Displays awesome progress bar using unicode characters), command-line argument `-u` or `--unicode` ![2013-08-11 14 27 47](https://f.cloud.github.com/assets/3759759/943892/11e73e72-0279-11e3-8f0d-62ba300672d2.png)
 * reactivation [dynamic segmentation](http://www.internetdownloadmanager.com/support/segmentation.html)
 * Firefox cookies support
 * no-clobber (Skip files that are already downloaded) command-line argument `-c` or `--no-clobber`