CRAN release soilDB 2.5

[brownag]

As near as I can tell, we are ready for soilDB 2.5 to go to CRAN -- as long as everything looks good on the winbuilder side.

Here are some big ticket items we discussed on closed PR #121 -- goal was to have these done for CRAN release.

Done (thanks @smroecker & @dylanbeaudette for your work on these)
#112
#53
#45
#44
#38
#36

Still open:
#1

[brownag]

For the future: see also recent issues and fixes #124 #123 related to examples in soilDB docs

[dylanbeaudette]

Thanks everyone for addressing these issues. I don't think that we will have consensus on #1 in time for the stats class. I'd like to get all of the usual suspects together and make a decision.

[dylanbeaudette]

Finally figured out why soilDB was falling off CRAN: web APIs are periodically not available due to maintenance and this throws CRAN check errors. A simple fix:

• added .local_NASIS_defined() to soilDB, returns TRUE | FALSE
• API-related test have to run, but not continuously on CRAN servers

Be sure to add the following to any test that involves web API access. Tests should be gracefully skipped on machines that don't have a local_nasis ODBC data source defined.

# obvious 
skip_if_offline()
  
# hack for in-house testing only
# WWW services aren't always available and will cause CRAN to drop our package if tests fail
if(! soilDB:::.local_NASIS_defined()) {
   skip("in-house testing only")
}

We may still have problems if examples, even inside of \donttest{}. We will see.

[brownag]

soilDB 2.5.0 is on CRAN as of midday today

https://github.com/ncss-tech/soilDB/releases/tag/2.5