Attaching sources for mapstruct-jdk8 module
#220 Allow getter as target accessor for Map types
#220 don't create new instances for collection/map properties when using addAll/putAll
#220 Avoiding negated method name
#178 fix a new unused import that crept in, added a test for it
#187 introducing constant mapping
#187 adding unit test to make sure that reverse mapping also works for source constants
#187 adapting for #198
#187 Minor clean-up and formatting
#187 Improving JavaDoc, adding new attribute to JDK 8 version of @Mapping