Factored out some code from TargetPlatformProperty.
Added IdentityValueDef
Generalized code in CommonProperties.
Added SourceLevelProperty definition.
Made some methods private (being public was unintended).
Added SourceLevelProperty.getProperty
Added BuildPlatformProperty.
Factored out code from PropertyDef.
Removed unnecessary code from TargetPlatformProperty.
Removed unnecessary code from BuildPlatformProperty.
Added CommonProperties.getIdentityKeyEncodingDef
Factored out code from SourceLevelProperty.
Added SourceEncodingProperty.
Factored out some code from AbstractProjectProperties
Fixed possible NPE in BuildPlatformProperty.
Implemented an unimplemented method in SourceEncodingProperty.
Added GradleLocationProperty.
Factored out code from AbstractProjectProperties.
Added ConfigTree.getChildTrees
Added LicenseHeaderInfoProperty.