MuJava++ 1.5.3 toughness analysis added

This updates brings support for toughness analysis.

This analysis is done for each mutant by the formula 1 - (failing tests / total tests) and an average toughness calculated by the sum of each mutant toughness value divided the total of mutants.

A new properties key is now supported:

mutation.advanced.toughness= [BOOLEAN]

Notice that if toughness analysis is enabled then quick death is disabled.

This updates also fixes an issue that caused JUnit tests with only @Test tags not being recognized as JUnit tests

This release only updates the mujava.jar, for other files (such as configuration and libraries) please refer to the 1.5 release.