Rewrite of the paths, connected path tiles

After the previous blog, I got a message from one Lord who found you could crash the program by building paths off the world (thanks for finding that, Lord).

Unfortunately, fixing proved difficult due to my somewhat naive way of coding it. There were three parties responsible: the world display, the path window, and a helper object that stored some selections. Rather than finding out who to blame exactly, I decided to rewrite it all, making the helper object the central entity. While you cannot see it at the outside, this makes the code much easier to deal with errors, since you know where to look. I fixed the off-world build problem, as well as few other problems.

Also invisible is the introduction of time. The game now keeps track of days, months and years.
Last but not least, the path tile building was changed to extend the edges of adjacent path tiles, which makes a much nicer path as you can see.