This function creates a table from excel sheets. This is mainly used
internally for building spec readers, but is exported so others who need to
build spec readers can use it.
Usage
create_tbl(doc, cols)
Value
dataset (or list of datasets if not specific enough)
Arguments
doc
list of sheets from a excel doc
cols
vector of regex to get a datasets base on which columns it has.
If the vector is named it will also rename the columns