ACT-1052 Activiti-cdi: Upgrade Jboss Weld to resolve Issue with BeforeShutdown event in ActivitiExtension

ACT-862: Removed duplicated calling of "ensureVariableInstancesInitialized()" and changed the implementation of "getVariableNames()" that in this case the values of the variables will not be loaded

- Added test 'testVariableNamesScope' and corresponding bpmn20.xml to reproduce error by using a command accessing ExecutionEntity.getVariableNames() and ExecutionEntity.getVariableNamesLocal()
- Fixed error by introducing method collectParentVariables which is used by both, getVariables() and getVariableNames().

Added check for headless instance to testParseDiagramInterchangeElements and adjust assertion when test is running on a headless instance like a linux continuous integration server to get a successful test.

Removing OSGi dynamic import from activiti-engine module (which I had committed in r3044), as this causes OSGi services to be restarted when delegates are deployed and used for the first time.

Changed SetProcessDefinitionVersionCmd to use a process definition version instead of its id as discussed in http://forums.activiti.org/en/viewtopic.php?t=2918

Added SetProcessDefinitionVersionCmd as discussed in http://forums.activiti.org/en/viewtopic.php?t=2918

ACT-990 moved test base classes to src/java/test

Updated WELD version to 1.1.3.SP1 because they fixed https://issues.jboss.org/browse/WELD-891 so we can now properly close the processengine on weld shutdown via our extension.

Added test cases for querying process instances by float, char and byte variable values, which results in a ActivitiException stating that "Variables of type ByteArray cannot be used to query"