Add scheme packages
Add dired-x, especially the awesome dired-jump
Use company for auto completion

The point is to test it and see how it works. All because geiser works
with this already, so I don't need to do anything more. Although, jedi
does not work with company, so for Python I'd need to switch to
ropemacs, which is said to be a lot worse in completion department.

We'll see what happens.
Improve completion configuration

- Do not start completions on cursor movement.
- Enable forcing completion start using a key binding.
Teach emacs clang arguments are safe to be set
Divide init file into modules