Some preset fields like the access-restriction field manage
multiple tags at once (access=*, foot=*, bicycle=*, …). Then
iD wasn't able to show inline help when clicking the ⓘ button.
This introduces a new parameter for these kind of fields:
`referenceKey` determines the tag key which should be used to
search taginfo documentation for.
Fixes#2222.
The [values](http://taginfo.openstreetmap.org/keys/addr%3Ahousename#values) of this rarely needed tag, which is prominent in the address presets, now have a lot of numbers and descriptive words in many different languages. Removing the preset means that new editors won’t fill this key with information useless to the key but can still add it through All tags if needed. A similar thing happened when Potlatch put the designation tag into presets. Goes towards #1427 and #2124.
This makes sure that the originals of changed entities get merged
into the base of the stack after restoring the data from JSON.
This is necessary, because the stack will only have elements for
the current viewport after a restart and previously *modified*
objects will now be falsely detected as *created* ones.
Also removed some ineffective code.
Incomplete multipolygons were harmed in the merge operation (which
relies on completely loaded relations to determine inner/outer
status for example).
This disables the operation and adds an appropriate tooltip.
previously when merging polygons, all tags from all involved
members were merged into the resulting multipolygon. This includes
existing inner members with different tags or outer members that
are not directly involved in the merge operations.
Example: A forest (landuse=forest) containing some clearings
(landuse=meadow), whose outline is in part a river (waterway=river)
is merged with a new untagged area. The resulting multipolygon
would have falsely been tagged: landuse=forest;meadow + waterway=river
Martin Raifer