Add bottomLayoutGuide to support iPhone 10 home button

[xamoom-raphael]

Add the bottomLayoutGuide to the visual constraint to have the Cancel-Button adjust to the new home button on iPhone 10.
Also add a LaunchScreen because without it wont use the whole iPhone 10 screen and have black bars on top and bottom.

Sorry for the strange empty rows, the real change starts in QRCodeReaderViewController.m at line 255.

[codecov-io]

Codecov Report

Merging #38 into master will decrease coverage by 0.02%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master     #38      +/-   ##
=========================================
- Coverage    5.42%   5.39%   -0.03%     
=========================================
  Files           9       9              
  Lines         387     389       +2     
  Branches       26      26              
=========================================
  Hits           21      21              
- Misses        364     366       +2     
  Partials        2       2

Impacted Files	Coverage Δ
...eReaderViewController/QRCodeReaderViewController.m	0% <0%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5366468...26c7394. Read the comment docs.