Fix some problems with CLARIN endpoint tester

common/annis_query_parser.py

common/config.py

common/diagnostics.py

common/litterae_query_parser.py

common/litterae_response_parser.py

common/query_parser.py

common/tsakorpus_query_parser.py

common/tsakorpus_response_parser.py

common/views_logic.py

main.py

notes.txt

requirements.txt

static/diagnostic.xml

static/endpoint_description.xml

static/explain_response.xml

static/search_retrieve_response.xml