WIP
Merged with master
Renamed classes around implicit and explicit property building
Added additional extensions to extensions pom
Extensions should depend on current project version
Re-worked named typemaps
Removed unused test
Merge branch 'master' into gh43

Conflicts:
	core/src/main/java/org/modelmapper/config/Configuration.java
	core/src/main/java/org/modelmapper/internal/ExplicitMappingProgress.java
	core/src/main/java/org/modelmapper/internal/InheritingConfiguration.java
	core/src/main/java/org/modelmapper/internal/PropertyMappingImpl.java
	core/src/main/java/org/modelmapper/internal/ProxyFactory.java
	core/src/test/java/org/modelmapper/internal/ProxyFactoryTest.java