fine-tuning in package domain

[JorderGomes]

• src/main/java/org/repodriller/domain/Commit.java:130: OverrideBothEqualsAndHashcode: Ensure you override both equals() and hashCode()

• src/main/java/org/repodriller/domain/Commit.java:131: SimplifyConditional: No need to check for null before an instanceof

• src/main/java/org/repodriller/domain/Modification.java:76: UseLocaleWithCaseConversions: When doing a String.toLowerCase()/toUpperCase() call, use a Locale

• src/main/java/org/repodriller/domain/Modification.java:76: UseLocaleWithCaseConversions: When doing a String.toLowerCase()/toUpperCase() call, use a Locale

• src/main/java/org/repodriller/domain/Modification.java:80: UseLocaleWithCaseConversions: When doing a String.toLowerCase()/toUpperCase() call, use a Locale

• src/main/java/org/repodriller/domain/Modification.java:84: LiteralsFirstInComparisons: Position literals first in String comparisons