Added a static method AbstractBoundaryOperator::uniqueLabel().
Added a sanity check of block cluster truncation for hybrid-ACA-mode assembly.
Reduced verbosity of AcaGlobalAssembler.
Added SyntheticIntegralOperator::getContextsForInternalAndAuxiliaryOperators().
Reduced verbosity of synthetic operator assembly.

Time spent in construction of sparse matrices is only reported if
verbosity is set to HIGH.
Added a missing include, thus fixing a bug involving auto_ptr destructor
not being invoked.