Corrected some errors

data/data_constant_genes.rgn

src/main/java/model/genes/ConstantRegulatoryGene.java

src/main/java/model/genes/Gene.java

src/main/java/model/genes/RegulatoryGene.java

src/main/java/model/network/RegulatoryNetwork.java

...main/java/model/network/RegulatoryNetworkDataManager.java

src/main/java/model/regulators/Regulator.java

src/test/java/model/genes/ConstantRegulatoryGeneTest.java