Merge pull request #411 from emorency/OPAL-2190-crosstab

OPAL-2190: Contingency table improvements
OPAL-2223 Session id extraction fixed.
Remove line from logger to speed up things
Work on edit categories when multiple languages is set
Rename one letter variables
OPAL-2194 - used the actual certificate principal rather than the certificate alias when authenticating
Merge pull request #412 from kazoompa/bug-OPAL-2194

OPAL-2194
OPAL-2190: Support categorical variables of valueType boolean