Update patch (See first post)
Changes:
1. Earlier version entrance was limited from 2 to 4 tiles from shore line.
This was altered to 2 to unlimited. (a limit could speed up tunnel searches somewhat)
2. Spaghetti was eliminated in CmdBuildTunnel proc.

3. Tile will high-lite on top of crossing tunnel if encountered.
4. Speedup of tunnel finding code. (IsTunnelInWayDir)
Search stops now on any non valid slope.
Bugs not known so please report
Regards