clean up variable names

Some spatial layers have poorly named variables, for example:

``` r
library(macleish)
#> Loading required package: etl
#> Loading required package: dplyr
#>
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#>
#> filter, lag
#> The following objects are masked from 'package:base':
#>
#> intersect, setdiff, setequal, union
macleish_layers[["research"]]
#> Simple feature collection with 32 features and 11 fields
#> geometry type: POLYGON
#> dimension: XY
#> bbox: xmin: -72.68474 ymin: 42.45108 xmax: -72.67797 ymax: 42.45915
#> CRS: 4326
#> First 10 features:
#> OBJECTID Id GapControl BUFF_DIST Name Details Start_Year Professor
#> 1 1 0 0 0
#> 2 2 0 0 0
#> 3 3 0 0 0
#> 4 4 1 G 12 0
#> 5 5 2 C 12 0
#> 6 6 3 G 12 0
#> 7 7 4 C 12 0
#> 8 8 7 G 12 0
#> 9 9 8 C 12 0
#> 10 10 5 G 12 0
#> Year_Start Shape_Leng Shape_Area geometry
#> 1 0 75.30356 310.8627 POLYGON ((-72.68172 42.4531...
#> 2 0 129.98172 491.5150 POLYGON ((-72.68184 42.4531...
#> 3 0 52.90795 169.9880 POLYGON ((-72.68217 42.4554...
#> 4 0 75.30253 450.0957 POLYGON ((-72.67812 42.4515...
#> 5 0 75.30258 450.0963 POLYGON ((-72.67855 42.4514...
#> 6 0 75.30256 450.0961 POLYGON ((-72.67894 42.4523...
#> 7 0 75.30256 450.0961 POLYGON ((-72.67933 42.4526...
#> 8 0 75.30262 450.0968 POLYGON ((-72.68181 42.4534...
#> 9 0 75.30260 450.0965 POLYGON ((-72.68135 42.4537...
#> 10 0 75.30260 450.0965 POLYGON ((-72.68148 42.4522...
```

^{Created on 2020-08-28 by the [reprex package](https://reprex.tidyverse.org) (v0.3.0)}

What is `OBJECTID`, and `Id`, etc? Are these variables meaningful? Or helpful?

This may require talking to Paul or Reid to recover some institutional/knowledge.

Start with the spatial layers shown by macleish_layers[["research"]] and inspect the source data or processing entry points that define fields such as OBJECTID, Id, GapControl, and Year_Start. Consult Paul or Reid to establish which fields are meaningful and whether they should be renamed or removed. Done means the affected layer variables have an agreed, clearer treatment.

Written by the indexing model from the issue text.