Update Maven Configurations

[syoon2]

This PR:

• Updates the link for loading MathJax in Javadoc
  The old link was using v2.7.1, this PR bumps up to v2.7.9. Includes patches for CVE-2018-1999024 (fixed in MathJax v2.7.4).
• Tells Maven to use the same versioning key for Surefire and Failsafe (to keep dependency versions consistent)
• Removes the Java API detection suppression in Javadoc (first added by bafb5a1)
  The underlying cause was resolved in the upstream dependencies few versions ago, and the version JGraphT uses for build is no longer affected.
• Adds java.version property in pom (to keep compile and javadoc plugins consistent and free of hard-coded Java version)

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• I read and understood https://github.com/jgrapht/jgrapht/wiki/Become-a-Contributor
• I read and understood https://github.com/jgrapht/jgrapht/wiki/How-to-make-your-first-%28code%29-contribution
• I added unit tests
• I added documentation
• I followed the Coding and Style Conventions
• I have not modified HISTORY.md or CONTRIBUTORS.md
• I ensured that the git commit message is a good one

[jsichi]

Thanks for all the maintenance work!