Started the real code on the Qt Interface.

Started the real code on the Qt Interface:
1 - Open File already open files, it tries to not break the
Gtk version, but some methods on the GTK version still need
to be called inside Qt because the code is too tight-coupled.

2 - Close file already close files, same comments for the open
file dialog applies here.

3 - The code for adding new cylinders in the cylinder dialog
is done, already works and it's integrated with the system.
There's a need to implement the edit and delete now, but it
will be easyer since I'm starting to not get lost on the code.

4 - Some functions that were used to convert unities have been
moved to convert.h ( can be changed later, put there because
it's easyer to find something that converts in a convert.h =p )
because they were static functions that operated in the GTK version
but I need those functions in the Qt version too.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>