could item_upsert be more flexible or rigid?

[aappling-usgs]

If you create a new item using item_upsert with the title in info rather than title, the value in info$title gets silently ignored.

After logging in:

# create a new item (works as expected)
test_item <- item_upsert(title="books.json") 

# unexpected: the new item has the title "books.json" rather than "sbtools stuff".
item_upsert(test_item, title=NULL, info=list(title = "sbtools stuff"))
# This message was given:   "title is NULL - re-using title from input SB item"
# But it's not clear from the message that/why info$title is getting ignored

Possible approaches to clarify/change this behavior:

1. Make item_upsert more clearly restrictive: either noisily override title with info$title if info$title exists, or always throw an error if title is included in info.
2. Make item_upsert more flexible: allow for all sorts of item queries, rather than just queries by title. All sorts of queries are available through the ScienceBase API for UPSERT (https://my.usgs.gov/confluence/display/sciencebase/ScienceBase+Catalog+Item+REST+Services#ScienceBaseCatalogItemRESTServices-UPSERTRequests). Maybe the title arg could be replaced by a query_list arg with the same definition as query_list in query_sb?

[dblodgett-usgs]

upsert has always confused me. I want to go through and test a number of things that are currently untested and make sure they are documented clearly. Will work on this as part of that.