safely initialize TutorialViewController

for #98

see
https://developer.apple.com/library/IOs/documentation/General/Conceptual/CocoaEncyclopedia/Initialization/Initialization.html#//apple_ref/doc/uid/TP40010810-CH6-SW58
for initializer implementation advice.
capitalize 'Restricted to map area' header

for #96
fix bug in tap away gesture implementation

correctly assign the created gesture
rename scoped gesture for a bit of clarity

to separate the internally scoped gesture from the instance variable
that it'll be assigned to.
redesign restricted to map area grid header

bigger (44px tall) with an X to remove the restriction.

for #96
replace some magic strings with static class vars
replace magic string with static var
redesign restricted to map area list header

bigger (44px tall) with an X to remove the restriction

for #96
remove inaccurate comment
remove unused UIView tag
clear map restriction target is a control now

we're not using the parameter, but for clarity's sake update it
add some appledoc-style comments for container VC