[quick_tour] simplified drastically the first two sections of "The Big Picture" chapter
[quick_tour] simplified the "routing" section
[quick_tour] updated the "Controllers" section
[quick_tour] updated some screenshots
[quick_tour] finished the review of "The Big Picture" chapter
[quick_tour] updated "the view" chapter
[quick tour] simplified "the controller" chapter
[quick_tour] simplified "the architecture" chapter
[quick_tour] second pass to the "big picture" chapter
[quick tour] second pass to "the view" chapter