adjsut scrollView size
add switched for UIAutoResizing
add scroll view using constraints
change colors
made horizontal layout visual format a string
add a test view and label for testing constraints
refactor test label
center label in scroll view
use visual format for insets, NSLayoutConstraint constraintWithItem:... for the centering
add ContentView VC
update contraints
add common scrollView setup code
create four scrollViews
loadScrollViewWithNoConstraints
loadScrollViewWithNoConstraints 2
Set content view using explicit constraints, but its subviews don’t.
update .gitignore
update constraints so that all scrollviews have equal widths
Using explicit constraints throughout.
 Using constraints For labels but explicit contentSize and contentView frame.