general: add uncrustify script

The current style of nautilus is rather poor and mixes at least 3
different code styles.

Specific issues that affect the most common contributors to Nautilus
performance are:
- tabs for multiline alignment.
- mix of tabs and spaces.
- errors on no braced one liners conditionals.
- errors on non braced case statements with variable declarations.

So I would say requirements for the style is to address the previous
issues and also be a well known style. I don't want new contributors
to see a new style completely different from C books authors.

So far, I found Allman (aka BSD) style which seems the choice of most C
books authors as far as I can see on internet, and it address the
previous mentioned issues.

Since uncrustify doesn't support the aligment of parameters we do for
multiple stars "**", we also added a script made by Sebastian Wilmet
to align those.

As a matter of practicity I'm going to convert all Nautilus style to
this one, and if the next person who contributes most on Nautilus has
a different choice, please feel free to change it to whatever makes your
performance and your contributors performance the best.

https://bugzilla.gnome.org/show_bug.cgi?id=770564