Make debuggo transparent for control

[glaserL]

Javier suggested to create debuggo simply extend the control object to improve ease of use.

Ideally, using clingo with or without debuggo should only add a call to the Control() object of clingo. During solving, a user should be able to call

ctl = Control()
ctl.draw() # outputs nothing
ctl.solve()
ctl.draw() # outputs the solving history

[glaserL]

If possible, users should be able to keep their code just as it is, only changing the import statement

from clingo import Control, Model

into

from clingo import Model
from debuggo import Control

[glaserL]

we instead do:

from vizlo import Control
ctl = Control(["0"])
...