Rebasing FunctionBase from Operator to Expression.

libwccl/ops/affix.cpp

libwccl/ops/affix.h

libwccl/ops/and.cpp

libwccl/ops/and.h

libwccl/ops/conditional.h

libwccl/ops/constant.h

libwccl/ops/equals.h

libwccl/ops/formatters.cpp

libwccl/ops/functions.h

libwccl/ops/intersects.h

libwccl/ops/isinside.h

libwccl/ops/isoutside.h

libwccl/ops/issubsetof.h

libwccl/ops/logicalpredicate.cpp

libwccl/ops/logicalpredicate.h

libwccl/ops/nor.cpp

libwccl/ops/nor.h

libwccl/ops/or.cpp

libwccl/ops/or.h

libwccl/ops/regex.cpp