restructured classes
moved internal classes into a separate internal package
added some documentation to non public api of DiffConfig
renamed DiffConfig to Configuration
added some more documentation to private api
added some tests for the configuration
added some public documentation
added uts for CheckableComparatorFinder
added documentation to internal api
added some uts for exception factories
added uts for ClassSerializer
added uts for InQuotesSerializer
added uts for NullSerializer
extend public api documentation
added ut for ComparableComparator
unified test names
added some internal documentation
improved InQuotesSerializerTest
added license information to test classes
added uts for CheckableSerializerFinder