Special tools for relations, visual editor.

[mkyral]

Relation editing is not easy. Add, remove segments is complicated.

Would be nice to have a set of specific tools for relation editing, like add segment, remove segment from relation, split segment, show gaps, fill gaps

Also nice will be to have an special visual editor for route and public_transport relations with segment drag'n'drop support and "segment routing" support:

*) user will enter start and end node and some important transit nodes
*) route is proposed (base on relation type - foot paths, cycleways, highways are preferred)
*) user can adjust proposal by D'n'D segments to correct ways
*) when user finish, he confirm changes, ways are automatically split if needed and relation is created.