[emacs] Add file with the packages to installed/used.
[emacs] Function to setup/install a list of packages.

Retrieve packages from a specific packages list (througth ELPA, Marmelade,
...)
[emacs] Update the .emacs example.
[emacs] Updated appearance configuration file.
[emacs] Update the keybindings configuration file.
[emacs] Update the main emacs init file.

* Remove global variable related to the foggy emacs dir.
* Use 'require' instead of 'load'.
* Remove useless function.
[emacs] Update the LaTeX configuration file.
[emacs] Update the Org-Mode configuration file.
[emacs] Update the music configuration file.

Disable the Mingus (MPD client) package for now (not available on ELPA or
Marmelade mirrors).
[emacs] Update the 'revision control' configuration file.
[emacs] Update the Web configuration file.

* Only keep the 'erc' package.
* Remove the oauth and identica packages.
[emacs] Update the 'development' configuration file.