Exception when instantiating an empty entity.

[kerbymart]

When instantiating an entity with no parameters like;

DataFactoryEntity emptyEntity = new DataFactoryEntityBuilder().build();

It should be handled at compile-time to prevent NPEs.

java.lang.NullPointerException: environment

	at java.util.Objects.requireNonNull(Objects.java:228)
	at com.divroll.datafactory.builders.DataFactoryEntityBuilder$ImmutableDataFactoryEntity$InitShim.environment(DataFactoryEntityBuilder.java:728)
	at com.divroll.datafactory.builders.DataFactoryEntityBuilder$ImmutableDataFactoryEntity.<init>(DataFactoryEntityBuilder.java:701)
	at com.divroll.datafactory.builders.DataFactoryEntityBuilder$ImmutableDataFactoryEntity.<init>(DataFactoryEntityBuilder.java:656)
	at com.divroll.datafactory.builders.DataFactoryEntityBuilder.build(DataFactoryEntityBuilder.java:612)