Failing tests in isa-graphparser module

Hi,

Some of the tests are failing:

```
$ mvn test
# (...)
Results :

Tests in error:
  parserSCC(org.isatools.graph.parser.GraphParserTest)
  parserSCC2(org.isatools.graph.parser.GraphParserTest)

Tests run: 13, Failures: 0, Errors: 2, Skipped: 0
```
