bug: Calling printTypes on SniperJavaPrettyPrinter always causes a NullPointerException

[slarse]

Hi,

The printTypes method is broken for SniperJavaPrettyPrinter, it always causes a NullPointerException. It's caused by the implementation of printTypes in DefaultJavaPrettyPrinter passing null for the CU to calculate

spoon/src/main/java/spoon/reflect/visitor/DefaultJavaPrettyPrinter.java

Lines 2006 to 2010 in 1cc3c74

	@Override
	public String printTypes(CtType<?>... type) {
	calculate(null, Arrays.asList(type));
	return getResult();
	}

and the SniperJavaPrettyPrinter assuming that the CU is not null

spoon/src/main/java/spoon/support/sniper/SniperJavaPrettyPrinter.java

Lines 112 to 116 in 1cc3c74

	public void calculate(CtCompilationUnit compilationUnit, List<CtType<?>> types) {
	sourceCompilationUnit = compilationUnit;
	//use line separator of origin source file
	setLineSeparator(detectLineSeparator(compilationUnit.getOriginalSourceCode()));

I don't think it's possible for the sniper printer to do its job without the CU. Working on a PR.