Edit checks for weight cols and id cols in hts_prep_variable

[ashleyasmus]

This check fails for my dataset:

travelSurveyTools/R/hts_prep_variable.R

Lines 93 to 102 in bf48868

	# Check that there is a id and weight for every table
	if (length(data) != length(id_cols)) {
	stop("Each table in data must have a corresponding id in id_cols")
	}
	if (weighted) {
	if (length(data) != length(wt_cols)) {
	stop("Each table in data must have a corresponding weight in wt_cols")
	}
	}

The check should not look at the length of the id columns, but rather that each table in hts_data has an id in id_cols.
Something like:

missing_ids = lapply(hts_data, function(x) length(names(x)[names(x) %in% id_cols])==0)
any(unlist(missing_ids))

missing_wts = lapply(hts_data, function(x) length(names(x)[names(x) %in% wt_cols])==0)
any(unlist(missing_wts ))