GreatGroupFormativeElements() and multiple matches

[dylanbeaudette]

Need to use the same strategy as SubOrderFormativeElements().

GreatGroupFormativeElements('acrustoxic kanhaplustults')

This has to do with map_int() expecting a single value / element.

  x
 1. +-SoilTaxonomy::GreatGroupFormativeElements("acrustoxic kanhaplustults")
 2. | \-purrr::map_int(loc.start, .safelyPickNotNA)
 3. \-purrr:::stop_bad_element_vector(...)
 4.   \-purrr:::stop_bad_vector(...)
 5.     \-purrr:::stop_bad_type(...)

[brownag]

This issue is resolved since {purrr} dependency was dropped. Came with reorganization of the package in #14 and use of lookup table rather than pattern matching to determine parent-child relationships