Add support of the bbo-extension ontology

[grigobog]

• [x] Replace updated BBO ontology by the original on
• [x] Add the new bbo-extension ontology (http://onto.fel.cvut.cz/ontologies/bbo)
• [x] Update prefixes and imports in convertor
• [x] Make changes from the comments in pull request https://github.com/kbss-cvut/bpmn-convertor-examples/pull/33
• [x] Test how it works on bpmn-convertor-examples/processes/ucl$ ./bin/process-bpmn.sh (can be done on next meeting)

[grigobog]

• made changes from the comments in pull request https://github.com/kbss-cvut/bpmn-convertor-examples/pull/33
• tested on bpmn-convertor-examples/processes/ucl using script bpmn-convertor-examples/processes/ucl$ ./bin/process-bpmn.sh: finished without errors, updated bpmn and pre-stamp output files are present in the latest commits in the bpmn-convertor-examples proejct

[blcham]

resolved