Fix observation properties to not confusingly refer to variables! (#567)

* Revert to gerund

Though the style guide says to just use imperatives, "get started" just sounds weird. Also this is more consistent with "troubleshooting"

* merge

* merge

* stable release

* removed reference to fork

* updated procedures

* wee corrections

* recorrect

* wee changes

* wee changes

* remove branch sync procedures

* corrections from Hannah

* first revisions

* more revisions

* more work

* first cut of variable-per-column rewrite

* more work

* more work

* more work

* restore changes

* more changes

* more changes

* more changes

* more changes

* updates to json spec

* more edits

* multiple directories

* more changes

* more changes

* more edits

* remove headings from TOC

* minor edits

* more edits

* remove wrong image reference

* remove more headings from TOC

* revisions per Ajai and a new diagram

* remove image, replace by text

* mention that node and field order in MCF do not matter

* added mention of required option for subdirs

* added note about MCF

* move feedback from index page to FAQ

* added info on stat var groups

* wee fixes

* make feedback links nicer

* added detail about measuredProperty in variable per column

* fix typo

* revert output directory change

* fixed observation properties to refer to observations, not variables

custom_dc/custom_data.md

@@ -566,7 +566,7 @@ You must specify the provenance details under `sources.provenances`; this field
 {: #observation-properties} 
 observationProperties (implicit schema only)
 
-: Optional: Additional information about each variable contained in the CSV file. Whatever setting you specify will apply to all variables in the file. (If you need different properties among variables, put your variables in different CSV files.)
+: Optional: Additional information about each observation contained in the CSV file. Whatever setting you specify will apply to all observations in the file. (If you need different properties among observations, put them in different CSV files.)
 
 Currently, the following properties are supported:
 - [`unit`](/glossary.html#unit): The unit of measurement used in the observations. This is a string representing a currency, area, weight, volume, etc. For example, `SquareFoot`, `USD`, `Barrel`, etc.