some simplifications and restructuring

src/main/java/de/tla2b/TLA2B.java

src/main/java/de/tla2b/analysis/AbstractASTVisitor.java

src/main/java/de/tla2b/analysis/BOperation.java

src/main/java/de/tla2b/analysis/InstanceTransformation.java

src/main/java/de/tla2b/analysis/SpecAnalyser.java

src/main/java/de/tla2b/analysis/SymbolSorter.java

src/main/java/de/tla2b/analysis/TypeChecker.java

src/main/java/de/tla2b/config/ModuleOverrider.java

...main/java/de/tla2b/exceptions/TLA2BFrontEndException.java

src/main/java/de/tla2b/global/BBuildIns.java

src/main/java/de/tla2b/global/BBuiltInOPs.java

src/main/java/de/tla2b/translation/OperationsFinder.java

src/main/java/de/tla2b/util/FileUtils.java

src/main/java/de/tla2bAst/BAstCreator.java

src/main/java/de/tla2bAst/ExpressionTranslator.java

src/main/java/de/tla2bAst/Translator.java