Update SoilTaxonomyDendrogram.R

[brownag]

Here are some suggested changes to make SoilTaxonomyDendrogram() more robust to alternate data sources. If they seem reasonable these changes may be made here, and then ultimately replaced with a dedicated new function from SoilTaxonomy so that ordered factor representation can be reused in other functions.

[brownag]

Also in a3ea312 added level argument (should it be levels? I guess I am following SoilTaxonomy package argument naming convention) to specify trees that do not necessarily use all levels of hierarchy or do not go all the way to subgroup, for instance:

[dylanbeaudette]

OK, I like the level argument, and will modify further to not look for hard-coded elements within the SPC--that was always a messy shortcut. While this is a rather simple fix, changing column names in fetchOSD is not; will follow-up on that over in ncss-tech/soilDB#242 (comment)

I'd prefer to wait until after WCSS before merging this, unless I have a very productive weekend.

[brownag]

While this is a rather simple fix, changing column names in fetchOSD is not; will follow-up on that over in ncss-tech/soilDB#242 (comment)

Changing the default column names is not a condition of merging this PR. This PR simply adds support for users who have a SPC that has standard NASIS column names in it (and the level argument, which generally cuts down on the noisyness of larger or more diverse plots)

[brownag]

I think we should probably merge this and deal with any other remaining issues outside this PR.

[dylanbeaudette]

Thanks for discussion. Good to merge.