Issue 87: Stack efficient Euclidean method

Updated fix to issue 87. Removes tail recursive function call to save stack memory space at the cost of another integer.

[X] An issue was first created before opening this pull request
[X] The new code follows the contribution guidelines
[X] I have performed a self-review of my own code
[n/a] I have commented my code, particularly in hard-to-understand areas
The new loop is functionally identical to the old loop which was not specifically documented.
[n/a] I have made corresponding changes to the documentation
Nothing about the call or output has been changed to warrant a documentation change.
[X] My changes generate no new warnings
[X] I have added tests to ensure that prove my fix is effective or that my feature works
(tests already present)
[X] New and existing unit tests pass locally with my changes

aalhour / C-Sharp-Algorithms