Adds merge_headers option, which can be "both" (default), "row", "horizontal", or "none", similar to virtual_mode (but defined on the return object of a setDataListener callback, instead of as an optional argument). These new non-default modes disable merge behavior as described in "Column and row groups" in the documentation.
Adds
merge_headersoption, which can be"both"(default),"row","horizontal", or"none", similar tovirtual_mode(but defined on the return object of asetDataListenercallback, instead of as an optional argument). These new non-default modes disable merge behavior as described in "Column and row groups" in the documentation.Fixes #193