added the methods str.first and str.last to access the first and last…

[diop7]

… characters of a string str

SUMMARY

Implements necessary changes for #20

Reviewers: @numere-org/maintainers

IMPLEMENTATION

• Implementation: (Describe, what you've changed)
• Implementation test: (Describe the type of test, which you performed, and if it was successful)

DOCUMENTATION

• [x] ChangesLog updated
• [x] Code changes commented
• Documentation articles:
  • [x] corresponding documentation articles updated
  • [ ] new documentation articles created
  • [ ] not needed
• Language files:
  • [x] corresponding language files updated
  • [ ] not needed

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TESTS BY REVIEWERS

• [x] Added to the automatic SW tests
• [x] Tested manually

sMyName = "NumeRe*";
print "string <<" + sMyName + ">>";
sMyName.first == "N"
sMyName.last == "*"

sMyName = "";
print "string <<" + sMyName + ">>";
sMyName.first == ""
sMyName.last == ""