Consider distinguishing violations coming from critical and background phases

[pengyuejiang]

emop/emop-maven-plugin/src/main/java/edu/cornell/RppVmsMojo.java

Line 115 in 41f2412

// TODO: Implement a finer-grained RPP-VMS that distinguishes critical and background phase violations.

As the comment mentioned, currently new violations are aggregated together. Consider the option of separating critical and background violations by tagging them, for instance, "Specification X got violated in the critical/background phase."