document the columns returned by search_data

[ellisp]

That is, what do each of these 30 columns mean:

> res <- search_data("name:water", limit = 20)
> names(res)
 [1] "cache_last_updated"        "package_id"                "webstore_last_updated"    
 [4] "id"                        "size"                      "state"                    
 [7] "last_modified"             "hash"                      "description"              
[10] "format"                    "mimetype_inner"            "url_type"                 
[13] "mimetype"                  "cache_url"                 "name"                     
[16] "created"                   "url"                       "webstore_url"             
[19] "position"                  "revision_id"               "resource_type"            
[22] "verified_date"             "verified"                  "resource_locator_protocol"
[25] "resource_locator_function" "Description"               "autoupdate"               
[28] "datastore_active"          "wms_layer"                 "can_use"     

Only can_use is made in R, the others all come from data.gov.au. We should document them (certainly the most important) as a definition list in the helpfile for search-data.

[thejholloway]

https://toolkit.data.gov.au/index.php?title=Discovering_Metadata this the information on the data.gov.au metadata I can find so far, but it's not what we want.

[thejholloway]

This lists all of these fields but doesn't provide useful information about what they are http://docs.ckan.org/en/latest/api/