demoting fetchNASIS_pedons() and fetchNASIS_components() to internal functions

[smroecker]

As discussed I demoted fetchNASIS_pedons() and fetchNASIS_components to internal functions. They will no longer show up in the list of soilDB functions or help files.

[dylanbeaudette]

This looks good. Is this something that you want changed before the stats class? We need to get soilDB submitted to CRAN this week if that is going to happen.

I would like to see more detailed documentation on the fill and duplicates arguments as these invoke some incredibly complex machinery.

Before making any more changes, how about we all commit to fixing some of the outstanding issues:

• Ensure that new rock fragment sorting code gives similar results as old code #1
• consider alternative strategy for uncode() and drop.unused.levels #112
• conversion of NASIS data to factors should use ordered factors when appropriate #53
• documentation for soilDB::uncode() #45
• NASIS lab data functions aren't working as expected #44
• SDA and duplicate records #38
• un-mixing SSURGO / STATSGO in SDA #36

[brownag]

RE: #38 - SDA and duplicate records b1e713a

New warning from get_component_from_SDA when duplicates=FALSE (default) and mukey is in WHERE clause

 if(!duplicates & grepl(WHERE, pattern = "mukey")[1])
    warning("duplicates is set to FALSE and 'mukey' is in WHERE clause. Note: 'mukey' omitted from result.", call.=FALSE)

New entry in doc for duplicates argument to fetchSDA_component/get_component_from_SDA

logical; if TRUE a record is returned for each unique mukey (may be many per nationalmusym)