Keep record of syn(spec|plot) folder.
Add a save and open button.

Now, everytime sagui is open, it loads preset parameters. The user
has an option to save its current parameters and open it later.

At this time it lacks the follwing resources:
* It can only save to one file. There is no option to save to a
specific file.
* The Open and Save functions can only be acessed by the buttons.
Later I have to add these functions on the menu.