CUSDK-189: Removed dependency from diff library

[JaviCerveraIngram]

Added Diff class and tests directly to the SDK again, to remove the dependency from the external diff library which was maintained by me.

[codecov-commenter]

Codecov Report

Merging #149 (ca1cb6d) into master (11be769) will increase coverage by 0.48%.
The diff coverage is 99.60%.

@@            Coverage Diff             @@
##           master     #149      +/-   ##
==========================================
+ Coverage   96.80%   97.28%   +0.48%     
==========================================
  Files          31       32       +1     
  Lines        2407     2914     +507     
  Branches       18       16       -2     
==========================================
+ Hits         2330     2835     +505     
- Misses         74       79       +5     
+ Partials        3        0       -3     

Impacted Files	Coverage Δ
test/unit/DiffTest.hx	99.60% <99.60%> (ø)
test/unit/TestSuite.hx	100.00% <100.00%> (ø)
test/unit/FlowTest.hx	88.05% <0.00%> (ø)
test/unit/FlowAttemptsTest.hx	75.00% <0.00%> (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 11be769...ca1cb6d. Read the comment docs.