Fixes two problems with Substation

[Vanuan]

http://wiki.openstreetmap.org/wiki/Tag:power%3Dsub_station

1. substation -> sub_station.
2. Substations are usually buildings (doesn't apply to points unfortunately).

[jfirebaugh]

Not convinced about building=yes. The wiki shows an outdoor area, which is what most substations I've seen look like, and according to taginfo only 30% of power=sub_station features are building=yes. I believe the correct tagging will in most cases be to tag the overall area as power=sub_station and individual buildings on premise with building=yes.

[jfirebaugh]

Merged the substation -> sub_station correction, thanks!

[Vanuan]

See my comments in #1214. Without "building=yes", this preset is useless, i.e.:

1. it doesn't refrect currently mapped features with "power=sub_station", "building"="yes" tags as a Substation
2. "create a Substation -> deselect -> click substation" workflow doesn't work
3. clicking an existing (correctly mapped) feature with "building=yes" or "area"="yes" and setting a Substation preset removes "building"="yes" tag.

What's the use of this preset then?

[Vanuan]

The wiki shows an outdoor area, which is what most substations I've seen look like

What most substations I've seen look like this: http://wiki.openstreetmap.org/w/images/thumb/d/d3/Trafostation_Alter_Hellweg_IMGP4722_osm.jpg/300px-Trafostation_Alter_Hellweg_IMGP4722_osm.jpg

We're not talking here how to correctly map those, but how to adapt the editor to currently mapped state. Probably, area=yes should be applied to those that are not buildings automatically. I don't know. I only know that there is a bug.

[jfirebaugh]

Yes, there was another bug caused by iD not recognizing anything tagged with power=* as an area. Try http://www.openstreetmap.us/iD/master/ -- 1 and 2 should be fixed. Switching from the Building preset to the Substation preset will still remove building=yes -- that's largely by design because presets are currently exclusive. We don't yet have a concept of an auxiliary or secondary preset.