Add support for funicular routes

[claudiush]

Certain metro networks also include funicular railway routes:

• Funicular dos Guindais in Metro do Porto network (OSM-Relation)
• F1 and F3 in Metro Istanbul network

Some of them are currently incorrectly mapped as route=light_rail in OpenStreetMap, while there are more than 150 route relations with route=funicular.

Please allow funicular as route for the subway validator to allow a more complete capture of the world's public transport networks.

[zyphlar]

route=monorail and eventually a few aerialway trams are in this category as well, they may not always require a fee but there are many systems that travelers and tourists find confusing to navigate without GPS app support.