add MBProgressHUD as Git submodule
update ZipKit to 1.0.2
update Cocoa Lumberjack to 1.7.0
update About.html to refer to the correct 3rdparty software versions
add enum value AdditiveKnowledgeTypeNone to match the Fuego source code
set deployment target to 6.1 (#198)
fix deprecation warnings resulting from deployment target change (#198)
use string to configure Fuego with additive knowledge type

revision r1728 of the Fuego source code requires that a string is used
in the GTP command to configure the additive knowledge type (e.g.
„uct_param_policy knowledge_type greenpeep“ instead of
„uct_param_policy knowledge_type 1“)
remove iOS 5 compatibility methods (#198)
document deployment target 6.1 in README.md + NOTES.build (#198)
simplify board position table view selection handling on iPad (#198, #199)

this change is possible because we no longer have to support iOS 5 and
can now override tableView:shouldHighlightRowAtIndexPath:(). because of
that we no longer have to maintain each cell’s selectionStyle, and
because of *THAT* we don’t have to reload cells when the current board
position changes.

the behaviour described in issue #199 changes as a by-product of the
change in this commit: the „start of the game" board position table view
cell now has the wrong background color when the table view is scrolled
from bottom to top. the source of the problem, however, remains the
same and will be fixed in the next commit.
„start of the game" board position now has correct background color (fixes #199)

the main fix here is to *always* set the background color for all cells.
prior to this fix the background color was not set at all for the board
position 0 cell (i.e. the „start of the game“ cell). the cell reuse
mechanism of UITableView would therefore lead to an unexpected cell
background color.

because we now set the cell background color in
tableView:cellForRowAtIndexPath: instead of in
tableView:willDisplayCell:forRowAtIndexPath:, the latter method is no
longer needed.

because this also changes the timing of when the cell background color
is set, another smaller, unreported bug is fixed as a side-effect: the
cell detail text label sometimes and inexplicably had the wrong
background color. the cause for this was that setting the background
color in tableView:willDisplayCell:forRowAtIndexPath: simply happened
too late and that cell reuse again got the better of us.
next stone marker "A" no longer displayed after all moves are discarded (fixes #200)