game: Fix some issues reported by pylint:

W: 17, 8: Redefining built-in 'input' (redefined-builtin)
W:  3, 0: Unused import QtCore (unused-import)
W:  3, 0: Unused import QtGui (unused-import)
gui: Fix some issues reported by pylint:

W: 42, 8: Attribute 'grid' defined outside __init__ (attribute-defined-outside-init)
W: 25, 8: Attribute 'scoreLabel' defined outside __init__ (attribute-defined-outside-init)
W: 43, 8: Attribute 'gridWidget' defined outside __init__ (attribute-defined-outside-init)
W:  1, 0: Unused import random (unused-import)
grid: Add getters for some private members.
gridWidget: Fix some issues reported by pylint:

W: 55, 0: Redefining name 'grid' from outer scope (line 3) (redefined-outer-name)
W: 70,25: Redefining built-in 'dir' (redefined-builtin)
W: 93,22: Access to a protected member _cols of a client class (protected-access)
W: 94,23: Access to a protected member _rows of a client class (protected-access)
W:187,21: Access to a protected member _horiz of a client class (protected-access)
W:  4, 0: Unused import network (unused-import)
W:  1, 0: Unused import sys (unused-import)