v0.9.1

• #53 Remove CRC32 in favor of java.util.zip.CRC32
• #52 Transition to JUnit 5
• #51 Add UnmodifiableCompositeCollection and UnmodifiableCompositeSet
• #50 Implement SortedSetArrayList
• #49 Implement Comparators.HASHCODE_COMPARATOR and Comparators.IDENTITY_HASHCODE_COMPARATOR
• #48 Implement Dates.currentTimeMins()