Client request implementations enforce RFC 6265 (cookies in a single header)

Issue: SPR-12196
Polishing

Issue: SPR-12196
ConfigurationClassParser avoids double registration of nested classes which extend their containing class

Issue: SPR-12195
GenericTypeAwarePropertyDescriptor implements equals/hashCode for proper lookups on IBM JVM 6

Issue: SPR-12185
WebMvcConfigurationSupport uses static NoOpValidator instead of anonymous inner class
Latest dependency updates (Reactor 1.1.4, Undertow 1.0.16)
GenericTypeAwarePropertyDescriptor implements equals/hashCode for proper lookups on IBM JVM 6

Issue: SPR-12185