Enhance CRT transformations from OSM to ISOM/ISSprOM/ISSkiOM symbol sets

[jmacura]

Adding more OSM tags which can be translated into orienteering map symbols. Namely:

• natural=peak
• leisure=picnic_table
• highway=primary_link
• highway=secondary_link
• highway=tertiary_link
• highway=steps
• tourism=information (restricted to guidepost, map or board)
• historic=memorial
• historic=wayside_cross

All of these I considered useful when I was preparing a base for my latest map.

[jmacura]

I am sorry, but I have no idea what to do with the failing tests...

[dg0yt]

Thanks @jmacura.

I am sorry, but I have no idea what to do with the failing tests...

This should be unrelated to the PR. No action needed from your side at the moment.