need data_* functions to extract data in various forms

[paleolimbot]

Probably something like...

data_plong() # parameter long (the default)
data_pwide(value = "value") # parameter wide using spread(key = param, value = value)
data_xwide(value = "value") # spread(key = x_columns[1], value = value)
data_lwide(value = "value") # spread(key = location, value = value)
data_dwide(value = "value") # spread
data_spread(...) # spread(...)