Update Tests directory structure

[mac-gallagher]

• Update Tests/ directory structure
• Rename test files from *Spec to *Test
• Add back iPad deployments for ShuffleExample (removed accidentally)
• Deleted duplicate CONTRIBUTING.md file under Documentation/
• Prefer UIKit imports over Foundation and CoreGraphics to avoid Swift PM build issues (from similar past experiences)
• Fix some indentation issues

[codecov-io]

Codecov Report

Merging #135 (da2a5b3) into master (90adc0e) will not change coverage.
The diff coverage is n/a.

❗ Current head da2a5b3 differs from pull request most recent head 298e096. Consider uploading reports for the commit 298e096 to get more accurate results

@@          Coverage Diff           @@
##           master    #135   +/-   ##
======================================
  Coverage    84.8%   84.8%           
======================================
  Files          13      13           
  Lines         759     759           
======================================
  Hits          644     644           
  Misses        115     115           

Impacted Files	Coverage Δ
...ses/SwipeCardStack/CardStackAnimationOptions.swift	100.0% <ø> (ø)
...fle/Classes/SwipeCardStack/CardStackAnimator.swift	0.0% <ø> (ø)
...Classes/SwipeCardStack/CardStackStateManager.swift	100.0% <ø> (ø)