Mechanism for marking slow running tests with JUnit groups/categories.

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
Marking several slow running tests across various modules.

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
Formatting pom.

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
Run slow tests by invoking 'mvn test -Pslow-tests'.

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>