Add japicmp plugin

[viartemev]

issue: #345

[cowtowncoder]

@viartemev Sounds good -- just one question on procedures. I will try to coordinate releases better, and perhaps we can give you and @dinomite Sonatype rights to be able to publish new versions. But just in case I will be responsible for at least some release publishing, it may be necessary to figure out procedure for updating old version (that is, how to update it), and perhaps also what to do with flagged changes (there will very likely be case where something is warned about but is considered not an actual issue).

[dinomite]

I guess this is expected for the diff from 2.10.4 and master; is there a way we can ignore this so Travis can pass on this branch? Should we backport this change to the active branches?

Failed to execute goal com.github.siom79.japicmp:japicmp-maven-plugin:0.14.3:cmp (default) on project jackson-module-kotlin:
There is at least one incompatibility:
com.fasterxml.jackson.module.kotlin.ExtensionsKt.registerKotlinModule(com.fasterxml.jackson.databind.ObjectMapper):METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.KotlinAnnotationIntrospector.findSubtypes(com.fasterxml.jackson.databind.introspect.Annotated):METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.KotlinAnnotationIntrospector.hasRequiredMarker(com.fasterxml.jackson.databind.introspect.AnnotatedMember):METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.KotlinInstantiators.findValueInstantiator(com.fasterxml.jackson.databind.DeserializationConfig
com.fasterxml.jackson.databind.BeanDescription
com.fasterxml.jackson.databind.deser.ValueInstantiator):METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.KotlinModule.getNullisSameAsDefault():METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.KotlinNamesAnnotationIntrospector.findImplicitPropertyName(com.fasterxml.jackson.databind.introspect.AnnotatedMember):METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.KotlinNamesAnnotationIntrospector.hasCreatorAnnotation(com.fasterxml.jackson.databind.introspect.Annotated):METHOD_REMOVED
com.fasterxml.jackson.databind.deser.ContextualDeserializer[com.fasterxml.jackson.databind.deser.ContextualDeserializer]:INTERFACE_REMOVED
com.fasterxml.jackson.databind.deser.ResolvableDeserializer[com.fasterxml.jackson.databind.deser.ResolvableDeserializer]:INTERFACE_REMOVED
com.fasterxml.jackson.module.kotlin.KotlinSerializers.findSerializer(com.fasterxml.jackson.databind.SerializationConfig
com.fasterxml.jackson.databind.JavaType
com.fasterxml.jackson.databind.BeanDescription):METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException.getMsg():METHOD_REMOVED
com.fasterxml.jackson.module.kotlin.MissingKotlinParameterException.getProcessor():METHOD_REMOVED -> [Help 1]

[dinomite]

Closing in favor of PR 424 against 2.12.