use separate default komi for area and territory scoring (#30)

default komi for area scoring is 6.5, for territory scoring it is 7.5.
if possible, user defaults are updated to use the new default. in
addition, komi is changed automatically to one of the defaults when the
user switches between scoring systems in the "New game" screen.
Game info screen now displays captured stones in move statistics section (#30)

the upcoming area scoring will not display captured stones anymore
because they are not relevant in the area scoring system. some users
might still be interested to know the numbers, so we include them in
the move statistics.
area scoring bugfixes (#30)

fix a few bugs frm the previous commits:
- NewGameCommand now applies the selected scoring system to the new game
- GoScore correctly updates the total white score
- Komi is not updated automatically on „New game“ screen when a game
  from the archive is loaded (.sgf files specify their own komi)
Game info screen now displays area scoring properties