WELD-1437 - Weld can't coexist with another CDI container in a large multi-module project.

1) Fix - ignore @AfterBeanDiscovery if thrown by non-weld CDI implementation

2) Test added -> problems arised with OWB scanning and validating classes in org.jboss.weld.environment.se.test packages:
 - needed to add @Alternative to a @Vetoed class (because OWB 1.2.0 is a CDI 1.0 impl. and doesn't know @Vetoed annotation)
 - cannot ignore BeforeBeanDiscovery event in org.jboss.weld.environment.se.WeldSEBeanRegistrant#registerWeldSEBeans because weld-se specific org.jboss.weld.environment.se.beans.ParametersFactory produces object needed for org.jboss.weld.environment.se.test.beans.ParametersTestBean's constructor injection.

I kind of doubt whether we need those tests.